Update 1.2.3 includes some hotfixes. After some research, I managed to regained access to the hidden adventure in Unity. Therefore, I implemented some fixes and improvements.
I've also finally made a demo version of the game. I am working on releasing it on Steam, so you can download it for free and play through the first half of the game.
I've added a few things to the hidden adventure. You now have an additional way to progress through the first part of the hidden adventure, which comes at the cost of an extra challenge in the second part. Also, there is a slight visual upgrade to all parts of the hidden adventure. I've also re-enabled post-processing and fog, which was missing in the last Update.
Additionally, I've added the current version number to the bottom-right corner of the options screen.
The file size of the game increased a bit (to ~561 MB), because of some assets that were added.
Have fun!