Sidewize's plot revolves around four planets which get attacked by evil aliens. Now the player buckles on a jetpack to teach them a lesson, not entirely surprising by shooting them with a laser cannon. The planet order can be chosen freely.

The game is a horizontally scrolling shooter in which the protagonist has all directions to maneuver. This is necessary because enemies come in from both sides of the screen. There are various power ups to collect which grant advantages like improved weapons in six expansion stages, extra lives or a protective shield.