As RAD WARRIOR , your job is to single-handedly clear out the aliens who have invaded a desolate and destroyed post-nuclear earth. To have any chance of this, you must locate a sacred suit of armor. Not only will this protect you from radiation, and allow you to withstand some enemy contact, it also heals you, and enables you to float.
This means that the game has two distinct styles, with your character limited to jumping, and with only rocks (located around the screens) to throw. Once you find the suit you can fly around the ledges, shoot the inbuilt Pulsar beam, and survive within the volcanic hideout the aliens have based themselves. You will need to recharge the suit at times, and also take it off to pass through tight caverns.