Insane, very geometry dash feel. For my liking, a little slower would have been nice, but you did implement some nice QOL jumping mechanics, in particular jump queueing, without which, I imagine it might have been impossible.
The timing for the end of the game was _spot on_ I had just sat there on the screen for awhile, catching my breath and being like, 'I don't know if I really want to play another level of this...' and then, the game just ended... Getting the difficulty just right like that, is quite a challenge in and of itself (or a really cool bit of slight of hand!)
In a way, this game isn't very mechanically tied to the limitation, one part of the game is basically a between level cutscene, while the other part is a level based version of an endless runner. I think it more than makes up for that though by so heavily tying the two elements together thematically (graphically) that it really sells the cost - the relationship between those two parts of the game.
If I had to dig for a complaint, I would say that a lot of the stage obstacles were too small to really get a clean read on what they were supposed to be at the speed the game was going. Many times you were using repetition, so could have done something similar with larger objects that would read better. Again, I think in general the game could have stood to be slower without detracting from the difficulty much, and in the early stages, in particular, I wanted release control on jumps, but the later stages were so fast and precise, I'm not sure that wouldn't have made the game harder in the end. Another weird one, is that it felt to me that your natural fall speed was a bit too fast. There were some platforms early that I really felt should be walk-offs but weren't. But that's mostly personal taste nitpicking. The game worked really well as a tense somewhat punishing platformer, with a dark theme.