The use of AI neural networks to up-res classic PC games has gained traction of late. We've seen it done for Doom, we've seen it done for Morrowind, and a whole host of emulated PlayStation games have been given the treatment.
But now, thanks to modder grandgreed, there's a neural network-created texture pack for the underrated FPS classic Heretic, taking in all surface textures, as well as enemy and pick-up sprites. Grandgreed was also responsible for the recent Hexen Neural Texture Pack.
There's a wealth of screenshots over on the Nexusmods page, and if you don't own the original game it's permanently very cheap on Steam. For now, here are a few images cherrypicked from the mod page (and thanks to DSO Gaming for the tip).