The game seems interesting and the characters have a nice hook.
I think the rat minigame needs to be looket at, the click doesn't seem to be registering properly, for mutants the click feels like playing duck hunt.
For mutant rats i had to right click twice before it let me register the 3 left clicks needed to kill and with the muttant rats being so fast i only managed to kill 3-5 of them, and sometimes it counts 1 kill as 2 for some reason
Edit: Aparently it's not registering some clicks, i used an autoclick to hit 5 times and it does kill the rat