Holy cow lol, I suddenly understand everything!
That was the final level--it was supposed to be impossible for you to get up onto that ledge, but I guess you pulled some frame-perfect tomfoolery. You were supposed to take the moveable door through the static door, ending the game.
The lag you experienced was actually time slowing down as you brought the doors closer together! It was supposed to be a cue that you should try and enter. Admittedly wasn't a great cue--in the post-jam build I plan to add some more FX.
Anyways, sorry this slipped past me (but I'm glad it'll be easy to fix!) Thank you for bringing this to my attention!