Other people have said this, but I think the rate at which speed increases could be doubled or maybe even tripled.
That being said, solid mechanics and an awesome soundtrack make this one of the best entries I've played. Got a soundcloud?
Viewing post in The Sisyphean Ninja Escape Sequence jam comments
Yes: https://soundcloud.com/firespike33 (a lot of the stuff on there is rather old and doesn't include my more recent soundtrack work on Coma State Eden and Now You've Made Me Crabby, but I might be adding some of those soon)
Regarding this game, if I make future builds I'll consider either making the speed increase faster or allowing the player to control it somehow, e.g. picking up an item that instantly boosts your speed and gives you a large score bonus.