Fun and short. I like how the last upgrade lets you annihilate the entire screen eventually, and surprised that my browser didn't crash despite taking the upgrades to pretty ludicrous levels.
Yeah, my browser freezes for a few seconds whenever I exit the upgrade menu...
Fun game though, even if it gets a bit boring when you need to click the upgrade all button over 2000 times to spend all your money, though. Wish there was a "spend all your money" button.