The third entry in the Oxyd series is also the first to be released on a purely commercial basis. Like its predecessors, it is a real-time puzzle game where the player maneuvers a rolling ball through a series of landscapes. Each landscape contains a number of "oxyd stones", which reveal colored symbols when hit, if the next stone you strike is an exact match, the two are unlocked. To complete a level, all matching pairs must be exposed.

Oxyd magnum! is single-player only, and contains 100 levels - each with a password, to let you continue later from the same point. The levels get progressively harder as new elements are thrown into the mix: pits, bumps, mazes, teleports, hidden passages, sliding and rotating blocks, deadly water, laser beams (and mirrors), tiles that reverse your controls, and many more. Some levels feature additional balls (controlled simultaneously or in turn), and others offer special items that let you manipulate the environment.