A visually well done entry.
I found the gameplay a bit confusing at first, i thought the mail post turret was meant to be on the enemies path until i realized that it was throwing projectile and thus could be put on floating platforms. After a few waves you get the gist of it though. Maybe this is in part due to the game's speed, since enemies move quite fast i didn't notice the projectile travelling toward them and thought the damage was done in melee.
All in all it's a pretty good entry. Good job.