Game is fun. Made it to wave 100 by only choosing to allow normies and blobs as enemies, taking the sprinkler, grenade launcher, and shotgun, and only giving the enemies damage upgrades. This led to the fire left by grenades instantly killing any enemy who touched it, which, in combination with some fire rate increases and enemy speed decreases, rendered the set-up unkillable. I could have continued, but there seems to be no end so I stopped. In the comments I see you have already realized you may need to address unkillable states via boomers; I thought you may find it helpful to know there are other unkillable states as well.