Not a bad attempt, I found it a bit difficult to start, you take a lot of damage from head on encounters (which you've given health packs for either way) and you need to dodge turrets constantly aiming at you (which you can destroy in most cases) - I think this difficulty spike is a bit high to start with, and the enemies sometimes seemed to hit me when using a hit and run tactic which didn't show through an animation.
All in all a good submission.