Gets boring fast. When you beat a level and then do the level again you have to refresh the page when you beat it again because it won't continue back to the main menu. Upgrades don't seem to do much till the last upgrade. Hell the weapon upgrade couldn't even kill the fly on the first level till it was maxed out. Fighting the other levels has no incentive to do them since you get the same amount of money no matter what level you choose and the only thing that changes is the enemy colors and how much damage your dealt. Level 1 is 1 heart level 2 is 2 hearts and level 3 is 3 hearts. The walls of the levels can be annoying as the enemy can get cheap hits if you get hung up on the pillars that are sticking out. Sometimes when trying to go through a door to the next room the doors will lock and you get fucked and have to refresh the page to fix it.@xcoldbloom rateo is short for rate of fire.