Very good for the most part. A couple fixes:
Rain and Lightning don't work. They spend your money immediately when you click on it and both the "yes" and "no" options result in you not getting the upgrade.
The wave counter also stops counting at some point, I didn't notice specifically where.
If you buy a weapon superior to the one you have equipped, it should equip automatically.
Finally, the plow trucks also stop working at times (I had 5 on waves 27-30 and couldn't use them).
 "Monster Mowdown 2"){kind=icon}
 "Doodle God"){kind=icon}