Fun game. I really liked planting and harvesting my own upgrades.
One small issue I had: The main menu didn't scale up with the window when I maximized it.
One curious feature: The muzzle location on the gun makes shooting a bit interesting. There's a safe zone inside my weapon radius where I can't shoot enemies. That's probably realistic, but it's a bit unconventional. I guess it'd be tricky to adjust, because you want bullets emerging from the end of the gun visually. (Come to think of it, I probably have the same problem in many of the games I've made. Thanks for the insight!)