Well done!
Really did appreciate the artistic style here. Action scenes were well made, and I also liked your use of different camera angles. It's nice to see the same shot happening from different perspectives (i.e. helicopter target, etc.)
A lot could be improved, of course, and although I don't want to complain about the length, it was a bit short.
Biggest thing your could work on OVERALL is making weapon turning more realistic, instead of tweening the weapon so that it's thinner. (Every time they turn a gun around, it looks like it's 2D). Might be cool to make it look as if you're going for 2D in the first place.
All in all, nice job.