Nice concept! The level design was pretty good, required a little bit of thinking and aiming.
Some criticisms:
The physics (collisions) were a little bit odd, though, and it was very weird for me that I couldn't jump.
Ability to know which portals were connected with each other would've been appreciated, though it wasn't that big a deal with these short levels.
The title screen only showed up after I beat the game. Music in the levels would've been nice.