A space shooter where you can switch between a red level and a blue level. The game is a horizontal scrolling shooter in which you take control of a jetpack propelled space warrior who travels between parallel universes and worm holes (hence 4-D or 4 dimensions) throughout the game. By flying over the top of the play field, you end up in an alternate universe. You travel back and forth defeating enemies until you reach a boss creature. On some occasions a worm hole will appear in the middle of the play field and you are taken to even stranger worlds.