I like the mouse-shield. What's fun is being in mid air and bouncing bullets back at the enemies.
But I do think the map could've been a little bigger (enemies swarm to the point of being a little cramped), and the jet pack could've been more instant. What I hate is jetpacking away from an enemy, only for the slow acceleration to prevent me from making my getaway. Could've been interesting if you'd make a full jump, *then* jetpack actually.
When I first played this, I interpreted it as shield basketball. Now I kind of want to see what that looks like :v Anyway, I had fun playing this. And I think the visuals and music do their role here well enough to hold up the rest. Good job.