I was about to report quite a few issues, but the video posted below already seems to cover most of them.

However, there seems to be a big issue with saves being completely broken on the Linux version now. The game produces a save.data but it seems to be corrupt in some way, as the game is unable to load it and always starts from the beginning (main menu and all on startup). Copying over a savefile from the Windows version works for one startup, while the Windows version also seems unable to load a Linux save, so it looks like an issue in the saving process rather than parsing the file. I tried looking at the log but there weren't any errors or anything there. Here's a broken save file right from the beginning of the game, if that helps: https://files.catbox.moe/a08sdi.data-linux

Didn't notice earlier the "known issues" section but ok

I think that I was playing on gamepad two demodays ago. Was it removed or it's something on my side? (tried bluetooth xbox one and wired xbox360)

Are you inspired by FEZ? (layers, 3D heart, binary puzzles)