A great start.
That was fun. I realize this is not a finished game, so I'll point out everything I think could use some tweaking.
First of all, I like the game overall. It's enjoyable and has all the makings of a really fun finished project.
I found the ship rotation a little odd. The pivot point seems to be the thruster. When you are moving fast, it's less noticable, but at slow speeds, it makes the movement pretty strange. I would center it on the ship.
The collision detection is kludgey. I hit many walls when I was not even touching them. I assume you are using a simple bounding box hit test. I would suggest either making the ship more square or using a more advanced collision check to avoid this problem.
The hints in the levels are nice, but they also get in the way. How about having them fade out after a set time or when you are near them?
I found that in several levels it was easier to just commit suicide rather than bother flying back past some obstacles. Obviously a life limit or ship damage guage would be a deterrent of such careless behavior.
The ship is small. While not a real problem, you must consider the repercussions. For instance, when the levels first appear, how about pointing out the ship to the player so they don't have to scan the playfield to figure out where they are? I lost plenty of bonus points just trying to find my ship.
The levels are fairly well built and have a lot of variety already. I think some different wall and obstacle graphics would be a considerable boon.
Finally, how about some bonuses like ship enhancements (faster, more maneuverability or acceleration/brakes, etc).
As I said, I know it's not finished, but it's a great start. I love the fact that the obstacles interact with the butons and teleports.