Really well polished game! The visuals and animation look spot on. I found the mechanic of mapping keys individually really interesting and would love to see the rest of those puzzles (and cool lore) that we missed :).
One suggestion I would give is on restarting a level, it would be nice if the text didn't pop up again (unless there's new dialog because of your death). That way it feels a little faster to jump back into the puzzle if you messed up (especially on the first level). Speaking of, I found it hilarious that you can just jump down the elevator shaft at the start xD.
Also, the game felt a little silent much of the time. More sound effects and maybe a quiet ambient track would be cool :).
Congrats on your first game!