This is an impressive demo that already feels ready to become a full game. I think it gets too difficult too soon (fewer spikes right at the start) and the controls are a bit off (I got an uncontrollable dash after getting the first Dash EX) but it otherwise has the right platforming feel.
However, the pills were a different problem. I don't think players want to mess around with stats during enemy encounters when these enemies are so quick to kill (doesn't help that the pills are limited too). Maybe if the pills gave the player short power-up effects (invisibility, one super punch, growing and shrinking in size) and worked on a cool-down I'd feel more eager to use them.
Sorry for the rambling, just wanted to say it's good :)