The graphs are really simple but work very well. The use of the theme is a classic idea. It is correctly used but making the player start all over again is probably too harsh if you add the time limit and some tedious spike placements.
I'd say that's a fair criticism especially for a game jam game. I did initially have checkpoints but they were spread throughout the level and didn't reset the timer so they felt redundant. For whatever reason I never considered it just could reset the loop you are on currently for some reason.
