Mouse and cats was nice (have got some mice starting to infiltrate nearby) - although, maybe have some more options than just keeping pressed the mouse button for firing? Not really familiar with these kinds of games, but like, the more damaging shot the longer you don't fire?
Have only gotten to wave 6, so, maybe there are more efficient ways than keeping mouse button pressed, but basically, am asking, what would change if the mouse kept always firing at cursor direction, even without a mouse press, which seems to be the meta, once again, without taking into account special abilities.