This game was fun. One thing I could immediately say is that I would allow space for jump. Having the sprint be k allowed the player to use two hands and this only would have been better had jump been space. It's hard to use one hand to control both movement and jumping. In the level where you're jumping the spikes (3rd, I think), I was on the second flag and you could jump through the wall and end up on the first level for some reason. That seemed odd. Sound would have really helped. Because it was for speed running, maybe add a timer? Other than that, it was fun. Well done!
Julian