I was able to get 336! Playing this game for a while can really hurt the pinky though. If the dash was mapped to my right hand that would help a lot with accessibility so that everything isn't on the left hand.
My first thought immediately with this game was that it made me feel like I was playing Quick Man's level in Megaman 2 (the one with the beams that instakill you as you fall to escape them!) Something I noticed was that it was often impossible to get power ups that make you bigger, and there were times where I was forced to take fall damage because of the way the platforms were set up.
I could definitely see this evolving into something more involved, keep up the good work!