This is just extremely difficult, which takes too much out of the game. The weapons don't do anything useful and the fact that they have limited ammo limits their use. And the controls are quite abhorrent, too, not aided by the fact that it's way too easy to just click out of the game. Jumping is very inconsistent as well, because it's not clear which press of the space button results in an evasive roll and which for a jump. The gameplay itself is solid if those issues were to be fixed. And also, once you get caught once it's impossible to not give up, because you get stuck in a gangbang. If there were any permanent upgrades in the game, it would make consequent tries easier and thus, doable, but that's not something I found so I cannot find this game entertaining whatsoever. And no, I don't mean the permanent upgrades you can buy within a run, I mean some upgrades you could get outside of the runs as to make waves easier from the beginning.
wave 21 first try after dropping game for 3 years, get good mate, this is matter of skill and i hope you will get enough skill (in shack you can jump on building with usage of platform, will help you a lot just use jump + 2 dodges, if you get the timing you'll basically won the whole wave and need to get down only to shoot dogs)