Momentum mechanics in platformers are really cool. I like what you're doing here, but some of the level design doesn't really align that well with this. It's a bit like having Sonic controls for a mario game haha. The start of level 1 was excellent though, bouncing over the bridges and moving quickly was fun, but the precise jumping afterwards less so. Still! Cool idea.
The sound effects are also a bit harsh as well, but there's some really easy tricks you can do in audacity to fix that stuff. Bitcrushing or using a lowpass filter will really warm up the audio.