Great take on the Jam's theme, nice job.

I think other than restarting the whole game, there should be a way to go back in time or back to a checkpoint when you get into an unsolvable situation. Or maybe just prevent unsolvable situations by letting the player pull the boxes, not just push them. There are also some collision bugs, but it's not really important, this still works very well as a proof of concept.

By the way, it reminds me of Rick & Morty s02e01, with the time ripple thing.

the puzzles using the blocks are super fun! you have to think 2 steps ahead, I also like the dungeon feel. 

I feel like it's not exactly "Just One"?

It's a cool dungeon though! I like how the enemy changes pattern in each color of room.