I played the game a bit. Looks cool, sounds good and movement mechanics are well made. The only thing is that I think the game needs a tutorial level or some other first level, that teaches all the starting mechanics properly. For example, I died several times before understood, that I need to use restler kick, when jumping over the pit. It would be cool to have a level, that shows the mechanics one after another in a safe environment.
In addition, sometimes enemies are hardly distinguishable from the background. The first mushroom you encounter can damage the player, because one can't see it. It was with me, as I enjoyed speeding up and running fast and didn't notice how I was running into that enemy. They should be made so, that a player certainly can notice them. Same goes to slimes, which are green on green background.
About dying. If the game is hard and you die often, game over screen should be skippable or really fast like in Super Meat Boy. For now it gets annoying, especially because of one-shot spikes and pits.
Overall, a fun platformer, will certainly play it more later.