Having to restart the entire level every time I died was pretty annoying, mostly because of how slowly the character moves. I don't think regular checkpoints are really necessary, more so just letting me move faster than a leisurely stroll. Getting caught on random parts of the ground wasn't a huge problem, but the game would feel much more finished if that were worked out. Probably the game's strongest point is the double jump, which feels unique, very consistent, and satisfying. The only complaint I have about the jump mechanic is the instructions. "Mash space" is pretty misleading, mashing space will get you as much height as a fast double tap, except you'll also wear out your spacebar. Maybe something more like "The closer the second jump to the first jump, the more height". I think this has potential if you design levels more around the difference in height you can get, for example sections with low-hanging spiked ceilings that force you to use low double jumps? All in all an enjoyable game, looking forward to the sequel!