Interesting take on destroying the package deliverers. The visuals are great and sound is initially great but having 8+ turrets firing at the same time became overwhelming. I also like the varying enemy types and turrets.
Once you place 2 $80 turrets, you are basically good for 30+ waves having consistent income and putting only $300 turrets. I got to wave 35 I believe, and they couldn't even get past the first turn.
A quick fix to make it harder could have been to allow multiple waves at the same time, just to see what kind of chaos transpires when you have a full field of turrets and enemies.