This man made a tank designed for paintball. A paintball tank. An actual tank, to be used for games of paintball.
There are some design flaws, of course. The driver is completely exposed, which is unforgivable. Unsupported track is less reliable than supported track (example of supported versus unsupported). Also, given the rapid rate of fire in paintball warfare, a firing system that provides only 50 rounds seems foolhardy. But his most glaring error is failing to show us someone getting hit with a huge paintball from extremely close range. Show us people getting hurt, dammit!
(Thanks to poonhound Ookie the Mutt)