Core Decay

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Ivar Hill Slipgate Ironworks™ · 3D Realms

Planned release: To be announced
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Last updated: 15 Sep 2026, 13:53 GMT

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16 posts

03 Dec 2024Developer post
Dev Blog #6: Post-Human
After a short hiatus, I bring you a new development update we're taking a look at how Core Decay approaches cybernetics, as both a gameplay feature and crucial part of the narrative and player identity! Dev Blog #6: Post-Human
02 Oct 2024Developer post
Location Showcase #1: Contingency Vault
Play Video In lieu of a dev blog post this month, today I'll be starting a series of visual location showcases to vary things up a bit! This will serve to show more of the game without spoiling all too much of the narrative content, and hopefully break up the walls of text of the
02 Sep 2024Developer post
Dev Blog #5: Cogito, Ergo Sum
Welcome back! This month's dev blog entry is going to be a bit shorter - which makes for a good opportunity to take a dive into the game's setting, story and thematic focus. This is an area I think is best left mostly unexplored in this dev blog in favor of experiencing it firsth
01 Aug 2024Developer post
Dev Blog #4: ICE Breaker
Welcome back to another Core Decay development blog post! This month we will take a closer look at a hugely important part of the game - computer terminals and hacking. While you can play through the game without engaging with hacking or cybersecurity at all, it can be a very pow
02 Jul 2024Developer post
Dev Blog #3: Real World Spaces
Welcome back to another Core Decay dev blog entry! This time we will be looking at how Core Decay approaches level design, looking at what motivates the way virtual spaces are designed and envisioned, and exploring a concrete example of this in how the design of a bank office has
10 Jun 2024Developer post
Dev Updates & New Forums!
Hello everyone - I want to introduce to you all the new Core Decay website at coredecay.com , and new forum at community.coredecay.com ! Moving forward, this website will be the central place where development updates and news will be posted moving forward, and where it is easies
02 Oct 2023PC Gamer
Cyborg immersive sim Core Decay still has those System Shock, Deus Ex vibes in a brand new trailer
Cyborg espionage game Core Decay has a new trailer out showcasing different approaches to the conundrum of being locked inside one of its sprawling, post-societal-collapse facilities. Our semi-cyber protagonist is faced with escaping a facility, which means traversing a living ar
30 Sep 2023Developer post
Core Decay - Realms Deep 2023 Trailer
Did you miss the Realms Deep showcase? Don't worry, we've got you covered with a new trailer from Core Decay. Inside, you can check out some of the different ways to approach the various sections of the game. And don't forget to look at our fresh, new key art. Wishlist Core Decay
Watch on YouTube
Did you miss the Realms Deep showcase? Don't worry, we've got you covered with a new trailer from Core Decay. Inside, you can check out some of the different ways to approach the various sections of the game.
And don't forget to look at our fresh, new key art.

Wishlist Core Decay here.
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Original post
06 Jul 2023Developer post
REALMS DEEP 2023 ANNOUNCEMENT
Realms Deep is back, baby! On September 30th, you are cordially invited to a late-night talk show event featuring our beloved host, Jared R Bair. 3D Realms brings updates from numerous titles under their diverse portfolio, including Its highly anticipated classic RTS Tempest Risi
05 Jun 2023Developer post
3D Realms Live! Interview - Ivar Hill (Lead Designer of Core Decay)
Recently, we had Lead Designer Ivar Hill on our livestream (Every Friday @ 2pm EST, 8pm CET on Twitch ) talking about the game and immersive sims in general. And you can watch it below. Don't forget-- Wishlist Core Decay if you haven't already. Follow us on Twitter . Follow us on
13 Mar 2023Developer post
Core Decay - Screenshot Saturday
We really appreciate the continued interest in Core Decay and we know that we've been silent for a bit, but the development continues according to schedule! In the spirit of that interest, here's a new screenshot that highlights a few of the changes that have been made since you
16 Sep 2022Developer post
Realms Deep 2022 starts today!
Realms Deep 2022, the annual digital showcase organized by 3D Realms and friends packed with world premieres and special guests, kicks off today at 12:00 PM PST / 09:00 PM CEST and continues over the weekend. Watch it live on 3D Realms' official Twitch and YouTube channels! And d
24 May 2022Developer post
Dev Blog Update #3: Welcome Back!
Welcome everyone to a Core Decay update! It's been a while since last time. Things have been a bit quiet due to team changes and new people coming onboard, but we are here to say that Core Decay is still being worked on and we think it's going to kick ass! Besides hearing from Iv
15 Aug 2021PC Gamer
Upcoming immersive sim Core Decay's getting a demo this year
Here's another titbit of info from this year's Realms Deep event, the digital showcase of retro shooters and the like coming from 3D Realms. Core Decay, an upcoming Shocklike (which is to say, a stealth-action FPS with some RPG elements) being made by Ivar Hill and Slipgate Ironw
29 May 2021Developer post
Dev Blog Update #2: The Core Decay Aesthetic
Welcome to the second dev blog entry for Core Decay! I’m Ivar Hill and I’m the Game Director of the project. Today I would like to delve into the visual style of the game, and how it is attempting to convey its world through its art style and aesthetics. But first, let me take a
Welcome to the second dev blog entry for Core Decay! I’m Ivar Hill and I’m the Game Director of the project.
Today I would like to delve into the visual style of the game, and how it is attempting to convey its world through its art style and aesthetics. But first, let me take a small detour to talk a bit about game aesthetics in general and particularly the surge of retro-inspired art styles that have been emerging for a while now.
Retro Aesthetics In Games
Needless to say, there have been a great many games with aesthetics that would be described as “pixely”, “low-res”, “old-school”, “retro” and so on.
What’s important to highlight here is that these visual styles emerged largely by necessity – due to technical limitations during the 80s and 90s, resolutions and color ranges had to be kept low. Artists were thus forced to work within very tight constraints – but even though the original premise was one of limitations, the emerging art often turned out evocative in its own right. This is an important point, since it is this that successful modern retro aesthetics attempt to emulate.
When an old school-inspired game is rather approached with the mindset of “It should be pixely since older games are pixely” it often leads to far worse results – it’s important to ask why you would want this sort of aesthetic. Simply wanting a game to emulate the style of its source of inspiration isn’t inherently bad, but it helps to understand why this aesthetic is interesting and engaging in the first place.
And why is this exactly? In most cases it comes down to abstraction – it’s the same reason you might value a Picasso for what it evokes rather than for being as close to photorealism as possible. At the very extreme on this spectrum we have things like ASCII games – something like Dwarf Fortress is evocative because it’s so minimalist that you paint your own picture of its world. In fact I wrote a short article on this topic here:
https://medium.com/@ivarhill/the-two-pixel-fish-odd-realm-and-the-beauty-of-inspirational-pixel-art-da3e748456fc
But higher-fidelity art styles can also have the same intent. Pixel art in general is a good example, but also aesthetics within 3D space. A game such as Quake is still incredibly atmospheric today for this very reason. It is also why one may consider a game such as Minecraft to be visually appealing – not despite its simplicity but because of it.
The Way We Remember
So how does this translate to Core Decay? In short, there are two main goals of the game’s art direction. One is derivative – it’s intended to evoke the way we remember old-school games to look, more so than the way they actually looked at the time. Two strong sources of inspiration here are Descent and Unreal 1, both with point filtered low resolution textures and atmospheric lighting. Core Decay reimagines this approach for a modern game, with more abstract textures that still feature modern rendering and lighting techniques.
The second goal is to be beautiful and immersive in its own right, regardless of what other games may have come before. Its combination of low-resolution art and modern rendering techniques is intended to look atmospheric and evocative – sometimes that’s all the justification you need! It may also come as a surprise that the game actually features things such as real-time reflections – but they are all in service to the overall aesthetic rather than simply added as an afterthought.
On the flip side, one thing I wanted to avoid – and thus is not present in the game – is specular and normal maps. I feel that this takes away from the textures as an abstract representation and makes them feel more like a physical material, which clashes with the overall art style.
Real-time reflections are cast on these shiny metal walls – however, said reflections are still point-filtered and low-res, blending in perfectly with the overall style.
Of course, all of this is a lot of words to simply say “The art style of Core Decay looks the way it does in order to look good”, which is obviously a bit of a meaningless statement to make. But the bottom line here is that every aspect of the aesthetic is deliberate and serves the visual identity of this game – it is not arbitrarily put in place to meet any sort of “retro-looking” criteria or to emulate the style of any one specific game that came before it.
Aesthetic Through Worldbuilding
There is far more to an art style than technical components, however! Equally critical is how the world itself is designed. Looking at a classic such as, say, Blade Runner, you cannot really separate the world from the aesthetics, the writing from the visuals. It’s all one coherent whole which feels unified in theme – and this holds equally true for games.
As discussed in the last dev blog entry, on both a gameplay level and a visual level Core Decay is heavily rooted in verisimilitude – and this is also reflected in its art. This is easier expressed as a set of rules:

Where does an object come from? Is it created by a known organization or corporation? Its design should reflect this.
Anything that is present should make logical sense. If a part rotates, lifts or moves, it should be obvious how this actually happens. If it emits light, the actual light source should be obvious. And so on. This doesn’t mean every little detail has to be completely accounted for, but the overall design should make sense.
Functionality is more important than coolness factor. If something looks badass, that’s awesome, but there should be a reason for its visual design within the game world.
The world is grim, but not devoid of color. Color schemes and saturation exist where it is logical, such as bright displays, coolant pipes in vivid colors, corporate logos and so on. Other, more mundane objects may look appropriately dull and desaturated by comparison.
This is just a smaller example but it should give an idea of how these sort of guiding principles also constitute part of the overall art style.
Dissecting A Core Decay Asset
So far all this has been a pretty abstract, high-level look at the art style of the game. Let’s more concretely look at an asset from the game, namely the Minelayer weapon which fires proximity mines.
The Proximity Mine is a very versatile tool in the player’s arsenal – it can be directly attached to walls and other surfaces without the need for a weapon at all, but when used together with the Minelayer it becomes particularly powerful. Fired at great distances, the player can set up traps from a safe location – or even fire the mines directly at an enemy upon which the weapon acts more as a grenade launcher!
Furthermore, many different kinds of mines exist at the player’s disposal – Frag Mines deal direct damage, Gas Mines cause non-lethal damage over time, and EMP Mines disable robotics.
For the actual Minelayer weapon, it needed to look utilitarian – not necessarily designed for military applications but closer to an industrial tool. Usually these assets are preceded by concept art, but in this case the weapon was created while Core Decay was still a solo project of mine so I went right into modelling as a means of blocking out various approaches. What I eventually ended up with was this:
There are a few things to note here. The overall approach to Core Decay models is to only add something into the actual mesh if it contributes to the object’s silhouette – anything else can be detailed up in the actual texture.
The actual design of the weapon also embodies the design philosophies mentioned above. All the mechanisms of its operation are in plain sight to the player – the mine canisters, the mechanism for revolving the magazine and inserting the canisters into the barrel, and so on.
Once the model itself is completed, the next step is texturing. In the case of the Minelayer, the final texture looks like this:
Note that this has been blown up by a factor of 2x for demonstration purposes – the actual texture is 256×256 pixels and any visible pixelation is solely a result of point filtering on the actual model.
The texture itself is hand-painted pixel by pixel, and also has lighting baked into it for further detail. Applied to the model, the final result looks like this:
As you can see, the texture adds a huge amount of detail to this asset – and one crucial aspect of Core Decay texturing is that the pixel borders (almost) always line up perfectly with the actual edges of the geometry. This yields the models an almost “3D pixel art” look which also fits very well with the overall style.
Also worth noting is that, as mentioned earlier, there are no specular or normal maps in the game. This is a simple diffuse map and an emission map for the glowy bits. Any perceived specularity is solely from the baked lighting and post processing.
Additionally, all weapons and other items in the game have a unique, handpainted icon that is used within the player’s inventory, with the minelayer looking like this:
In-game from a first-person view, the end result looks as follows:
Watch on YouTube
Finally, in addition to all of this, there’s also a number of other things that goes into making a weapon – particle effects, sound design, animation and much more! But in general this should give a good idea of the overall process behind the game’s art.
User Interface
One often forgotten aspect of a game’s visual expression is its UI art and design. I will be talking about this more in a separate dev blog post, since the topic very much deserves its own spotlight!
That being said, to sum this up shortly – usually game UIs lie somewhere on a spectrum between abstraction and skeuomorphism. Minimalist, abstract UIs have the benefit of getting out of the player’s way and highlight the rest of the game, which works very well in many cases. On the flip side, more skeuomorphic UIs can work as a wonderful way to further inject a sense of atmosphere and immersion into a game – something such as say, the Fallout 1/2 UIs are a great example of this.
Core Decay lies somewhere in the middle of this spectrum – its UI is not fully skeuomorphic in that it does not attempt to emulate any particular real-world material nor does it present itself in the actual game world. On the other hand it is not entirely abstract either, with its visual language evoking the same style of interface also present in in-game terminals or other locations. Hopefully the end result is a UI that feels atmospheric while still being clear and highly usable!
Conclusion
This wraps up a first look at the art style of Core Decay! There will be more similar posts in the future going over topics such as UI art, animation, level design and so on, so stay tuned! As always if you have any thoughts or questions, you’re very welcome to head over to the 3DR Discord server – https://discord.gg/3drealms – where there is a dedicated Core Decay channel. Thank you all for your time, and see you in the next update!
Original post
27 Apr 2021Developer post
Dev Blog Update #1: This is Core Decay
Welcome to the first dev blog entry for Core Decay! I’m Ivar Hill and I’m the Game Director of the project – those of you who have followed its development for a while will know me as having worked on Core Decay as a solo project for a number of years! Core Decay is, at its heart
Welcome to the first dev blog entry for Core Decay! I’m Ivar Hill and I’m the Game Director of the project – those of you who have followed its development for a while will know me as having worked on Core Decay as a solo project for a number of years!
Core Decay is, at its heart, a love letter to the immersive sims of the late 90s and early 2000s. As with games such as Deus Ex or System Shock, it places a heavy emphasis on presenting an intriguing setting, with a focus on open-ended exploration, immersion, and discovery.
As is a staple in the genre, it also makes for a soapbox to explore philosophical ideas – Core Decay’s story centers heavily around the nature of consciousness and humanity, and how in a desperation to survive we may find these ideas to be more mutable than we’d think.
Setting
Core Decay takes place in 2089 – this is a time of great desperation, as near-unlivable environmental conditions and shortages of vital resources have led to major societal shifts. Although – perhaps surprisingly – the world has been spared from larger military conflicts, society at large sees itself simply trying to survive year by year as living conditions are only getting worse.
Unbeknownst to the general public, things are even worse than they seem, and the Earth is about to reach an entirely non-survivable state much sooner than anticipated. There are, however, those who know – and this group of individuals is set to sacrifice everything to make sure that humanity can keep on surviving even when all else is lost.
It is in this world of despair that you awaken, unsure of who you are or what led you to the place you find yourself in – and throughout the game you will go on a great journey of discovery spanning five continents.
Level Design
The game is structured into ten locations across the Earth – each a large area to explore with its own narrative and atmosphere, and all part of the game’s larger storyline. Although Core Decay does not feature large hubs as such (akin to Deus Ex), most of the locations of the game are not entirely hostile – there will be people to talk to and many non-combat areas and approaches.
As with any immersive sim, the most significant focus of the game is offering you many ways to resolve objectives, with exploration and creativity being just as viable of a way forward as engaging in combat – often even more so!
The City Of Seversk
As an example, an early game level features an enclosed facility that you have to enter. This facility is located in Seversk, Siberia, and the heat and water it generates has attracted a small group of survivors who have made an encampment next to it, finding a way to survive even in the harshness of the Siberian winters.
This settlement of survivors, led by a previous facility employee named Mikhail, has been plagued by problems. Radiation leaking out of the plant is slowly poisoning the inhabitants. Furthermore, the facility water lines have been cut off leaving the settlement with no continuous source of water, and their stockpiles are running low.
To make matters even worse, friction within the settlement reached a breaking point – although Mikhail attempted to take a humanist approach and distribute the limited resources according to who needs them most, not everyone feels the same. In a dispute, a smaller group of people argued for a survival-of-the-fittest approach, and although not able to stage a full scale mutiny they nonetheless split up and formed their own smaller camp nearby.
Talking to Mikhail, he asks you for three favors. One is to re-establish the water connection to the facility, and therefore the settlement. The second is to approach the splinter group and convince them to rejoin the larger group, as he fears – rightfully – that they are staging a violent takeover. The third is to find a way to stop the radioactive emissions from slowly killing the settlement inhabitants.
If you approach the splinter group, their leader has an alternate suggestion – poison the water line connecting to the larger settlement, allowing them to move in and claim the resources for themselves.
Dealing with the water situation – or the survivors at large – is optional, but if you choose to do so, you have multiple ways to handle it. The water line can be fixed, which will gain Mikhail’s gratitude. Alternatively, you can poison the lines leading to the larger settlement – or just personally kill everyone within – which will let the splinter group move in, and let you retrieve facility access as a result. Finally, you can also poison both water lines, killing off all human survivors altogether.
If you choose the first option, the splinter group can also be dealt with. You can talk them into joining the larger settlement again by changing their viewpoints, which will make Mikhail very grateful – although it’s a difficult task. You can also convince the group to leave altogether, a less optimal solution but still pleasing Mikhail. Finally you can simply kill the splinter group, earning Mikhail’s disapproval unless sufficiently argued for in a later conversation with him.
In addition to all these various options, you can also engage either settlement in direct combat. Although very challenging it’s still possible to simply kill all the survivors, also gaining facility access as a result.
And as mentioned earlier, all of this is entirely optional, as this is just one among many ways to get into this facility!
Design Philosophy
From a broader design standpoint, Core Decay is developed with a focus on verisimilitude – or in other words, things should behave or present themselves in the way you logically expect them to. This doesn’t necessarily mean realism, though given the game’s near-future setting there’s definitely some overlap. A few examples of how this manifests itself in practice:

There are many areas of game levels which serve no specific gameplay or design purpose, but rather make sense in terms of how the location might have been constructed from a lore standpoint.
In-world pickups are placed in locations that make logical sense, rather than being arbitrary. A person who barricaded themselves into a room might have put ammunition in it, whereas an IT office might contain bypass tools.
There is no real-time map on the HUD. Rather, you might see maps on screens in the level, or be sent images over your comlink that you can look at for reference.
Doors that look like they could be destroyed with explosives, can be.
The game always explains or makes logically clear how you have reached a certain destination.
Avoiding enemies is a perfectly viable way to proceed – even ones important to the story.
Log entries usually comment on the world around them. A room is unexpectedly flooded? The nearby terminal probably mentions it, unless it happened after an evacuation.
Humor within the game is based on the personalities of whoever wrote emails/chats/log entries that you encounter. If whoever wrote a log entry has a certain sense of humor, that is reflected in their individual entries. If they are the serious type, that sets a different tone.
If you lose a leg, you move slower. If you lose both legs, you have to crawl until healed.
As can be seen in the above examples, this design philosophy is distinctly different from a gameplay-first approach. Rather than design around specific gameplay mechanics and have all other aspects follow – a methodology that works fantastically well for many subgenres of shooters! – in this case the focal point is the worldbuilding, narrative, and atmosphere. An approach that, I hope most will agree, is very suitable for a story-focused immersive sim :)
Gameplay Mechanics
Regardless, in terms of actual mechanics there’s many ways you can interact with the game world, all serving to provide you with a wide range of options at any given time.
Combat is usually a viable approach, although not necessarily the easiest or most straightforward one – the world around you is very dangerous and being selective about when to take the risk of engaging in combat is wise. At your disposal is a wide range of weapons (both lethal and non-lethal), as well as many ways to upgrade and enhance your combat ability.
Actual management of weapons and other equipment is done through a grid-based inventory, requiring you to strategically decide which equipment you want to keep throughout the game, balancing your available resources with your playstyle.
Apart from weapons and equipment, you can also install cybernetic implants into your body which has both combat and non-combat benefits. All cybernetic implants are passive in nature but can provide significant abilities! Run faster, jump higher, see through walls – the opportunities are endless!
It is not just dealing damage that has a lot of depth to it, however – taking damage does as well! When taking damage, it is absorbed by one or several of seven regions: your cranium, torso, abdomen, left arm, right arm, left leg, and right leg. Different sources of damage may spread differently – for instance, breathing in toxic gas mainly damages your torso, and falling from high heights mainly damages your legs. Once damaged, a body part may give you certain penalties until healed, and if entirely incapacitated you can suffer some quite drastic downsides!
There are also many objects around the world to interact with – most notably, computer terminals and PDAs which may contain interesting information or means to control various parts of the level. These also often provide a window into the lives of various inhabitants of the places you visit.
Apart from combat and exploration, the game also features stealth elements (though it’s worth noting that it is not primarily a stealth game – non-combat approach more often involves finding ways to avoid even getting close to hostiles!) as well as a dialogue system where you can talk to people (or non-people…) that you come across.
Closing thoughts
We have of course only scratched the surface of Core Decay within this post, but nonetheless I hope it may have shed some light on what this game is trying to be and what you might expect out of it! Some closing notes:
This is not Deus Ex 5
…having spent a couple thousand hours playing the Deus Ex series, I wish! :)
But no, in seriousness, I do want to make a point that despite drawing a lot of inspiration from games such as Deus Ex or System Shock, Core Decay is still very much its own thing. It is in the spirit of these classics but there’s a ton of things it does very differently – the last thing I’d want is for anyone to feel their expectations are not met. However, let me say this with great confidence: If you do enjoy Deus Ex or System Shock, there’s very much to enjoy for you in this game!
The game is early in development
I also want to iterate something I’ve mentioned in various places over the last few months – Core Decay is still very early in development! There’s a lot left to be done, so I’d recommend setting your expectations on a release date accordingly :)
Next on the dev blog
Future dev blog posts will be much more “behind the scenes”-like and show more insights into the development process. I wanted to make sure to present the game a bit closer first, but expect to see things like level design, coding and art sneak peeks as we move forward!If you have any thoughts or questions, you’re very welcome to head over to the 3DR Discord server – https://discord.gg/3drealms – where there is a dedicated Core Decay channel. Thank you all for your time, and see you in the next update! Je pense, donc je suis.
Original post