While the core mechanic is really cool and well done and the style is overall alright, precision platformer was not the genre for this mechanic. Maybe it could be alleviated a little if the past lives had a bit of a head-start on your current life, so you could move quickly without being completely blind. But the level of precision demanded in a couple sections was bordering on rage game levels, exacerbated by the high jump mechanic being a bit unwieldy. I can understand wanting to minimise the number of controls, but I think control for the high jump could have been improved somehow. The amount of times I died because of it was far too high, even after figuring out I could hold space before I land. The final section was pretty mean. I admit to starting to get frustrated with it.
Really cool game though! To be clear, I finished and enjoyed it. Some tighter controls and maybe easing up the precision a little are my main suggestions.