played 10min, got 550 rats :) no plague shall touch me! liked the game, it almost seemed like inverted difficulty ramping, since rats didnt get more health/harder rats to kill, spawnpattern became predicatable and i grew in strength. but i really liked it, i kinda wanted to get all the upgrades!
adding levels/maps and difficulty ramping would make the game playable for alot longer time and provide a fun experience!Good job!