Hey awesmeraphi!
I played a bit with your file and changed a lot of things so I'll not explain every bit. Just take a look at this .capx and let me know if this was what you were trying to achieve.
[attachment=0:3kbfnt19][/attachment:3kbfnt19]
(use the arrows to move and the space to shoot)
If you have any questions, just let me know...
I'd have some other suggestions regarding the behavior itself. For instance, instead of decreasing HP every 2 seconds by 100, I'd decrease it more frequently, in tinier portions. Also, I'd lose the decceleration thing, it is very annoying. Just put the decceleration higher than the acceleration and let the char make sharper turns and stops.
Cheers!