The Doomball is a literal ball of guns that swerves around on the walls(and sometimes midair) of its boss room. Doomball is only encountered in Battlements, The Warehouse, and Tog-O-Drome. Each variation differs slightly, but the core aspect of the boss fight stays the same.
Movement and Attack[]
The Doomball's movement is really simple as it circles around a fixed point and doesn't change direction. Its only attack is missiles that shoot out and home in on your position. The Doomball's only tricky side is that it can be a pain to shoot. As the boss fight progresses the Doomball increases in speed and shoots more missiles.
Strategy[]
You can either stay in the middle and shoot ahead of the Doomball or try to get in front of it and shoot it while constantly moving back and to the left. If in the middle, always stay moving and make small circular movements whenever the missiles get close.