cool game, I liked how short and self-contained it is...
some notes if you wanted any:
- really needs ambient sounds / world sounds during gameplay... the sound of wind at the top... computer beeping noises near computers... the sound of the ocean when you're at the bottom, etc.
- the backtracking up and down is a little tedious and feels unnecessary / artificial
- I would've displayed your current equipped key as the camera viewmodel, e.g. as if we're holding it (like a gun in a first person shooter)... I'm familiar with greek letters but I still sometimes forgot what I was carrying, I'd imagine it's more difficult if you don't know greek letters at all and you're trying to remember "curly round thing with a squiggle"