This is a fun idea :) Took me a while to get past the first double spike area (before building the staircase), but I got better as I retried. Adding a keyboard shortcut on the title screen to play the game would make those restarts feel quicker to get into.
Jump currently feels a bit awkward, but maybe even just a few milliseconds of no y/vertical change might help it feel a bit smoother and give us those vital extra 5 pixels or so to clear what are probably supposed to be easy intro jumps? Or, just slightly thinner hitboxes on the spikes to give us a tiny bit of grace for imperfect timing.
Enjoyed it and would happily play more if you're thinking of working on it post jam :)