When you have the momentum, this game can feel great. But when you lose that speed it's really frustrating. Especially when I try and dash uphill, it just loses speed immediately. But if I turn back and hit a downward slope and the make my way back up the upward slope, I don't lose speed.
I got lost a few times. You could put some arrows or something around the edges of the screen to point you in the direction of the next checkpoint, instead of only showing them when their position is in screen-space.
Make the red objects full bright or emissive or something. In shadow it's really difficult to see what is or isn't red.
I enjoyed what I played, keep at it.