Pretty neat, little platformer game. The graphics are quite pleasing, the music is sweet and the gameplay mechanics with those portals are quite interesting as well.
My only complainment would be that the game is a bit "glitchy", e.g. when I quickly press SPACE the character doesn't always react immediately and that's a bit annoying.
Also, a pretty common glitch that's in every single game in the worlld: I could sometimes go through the blocks and such.
In addition to that, I always get the menu thingy when I enter a new level, try to remove it then or something.
Anyways, good job on this neat platformer ^_^