I lasted 2 minutes and 48 seconds.
this game is indeed hard as heck, especially when you don't know what to do. but even getting the best character first means certain death. the solution is always spamming the weaker enemies and keep spamming it, in fact it becomes a better strategy that I don't see the reason for getting any other characters.
I don't have interest in defense games, but I can see a lot of work going on here, in fact too much work, I don't see the reason for 'retreat' to be an option, and clicking on ''cancel' might as well be a game over button.
other than that, I did try again and again to last at least 2 minutes, and that's enough for me.