By far one of the most polished jam submissions I've seen. At first I was thinking "oh, another Portal-ish puzzle game - this'll be quick," but then the hidden bits just kept coming. I loved the way you encouraged the player to seek out all the endings too. Very cool!
As a developer, I often struggle in coming up with interesting level design in a game jam setting. I'm curious if you'd mind sharing how you designed the game's level and layout, either here or in a dev log?