It's not peiyx://ehl.vnzz.vp/riitn but rather peiyx://ehl.vnzz.vp/riitns
This is the result of the decryption https://www.miro.gg/maxeen. It leads to this video.
I used this tool https://github.com/bruvzg/gdsdecomp
I have some Godot Engine background so it allowed me to make sense out of the output. The only thing I had trouble with were the STEX files which I didn't even try to convert to readable formats due to the lack of time. I doubt that there's anything worth looking for anyway so I'm going to leave it as it is.
I've also had some troubles with a couple of the stex files, but since the game is so small it's pretty easy to figure out what the textures are and if there are any textures we haven't seen.
Bark003_1K_Color.jpg
Bark003_1K_Color.png -- these 2 are the tree bark textures, I think one of them is just unused.
cracks.png -- the cracks that appear on your screen when you die
Ebar.png -- energy bar (full)
Ebarbottom.png -- energy bar (empty)
Finale.png -- most likely the text that gets revealed after pushing all 5 buttons
Ground.png -- the ground texture for the trees
icon.png -- just the godot logo
Instructions.png -- I assume it's the thing that shows you the controls
Leaves.png -- tree leaves
Noise.png -- the texture that is used for concrete
Pain.png -- probably gets used when you get hit, this one actually converts to png and its an outwards white gradient fading into read around the edges of the screen
Purchase goods.png -- should be pretty obvious
Rosetta.png -- probably the text that says 'the quick brown fox jumps over the lazy dog'
Saggitarius.png -- the enemy black hole thing
soft noise.png -- the texture that is used for benches
Very soft noise.png -- the texture that is used for the gem things that light up when you push the buttons (unless I read the file wrong)
these are all the textures in the pck