I love the look of the game!
I'm not a huge fan of the overly slide-y movement however. It felt quite imprecise combined with the player sliding down slopes, though I might just not be used to it.
Some of the platforms that look solid are actually not (the ones that the shoot dudes are standing on), maybe they should have a different more distinct colors from the main level geometry.
The checkpoints in the second and third level don't seem to work.