Krypton is a side view horizontal scrolling shooter where you control a Superhero as the screen scrolls from left to right constantly, as you try to save the Earth from attack by Superbeings over various levels. You crashed a space shuttle on Earth after a trip from your home planet, but instead of feeling sorry for yourself, you like living here and so you have vowed to protect your adopted planet from any threat armed with lasers shot from your eyes.
One such threat has appeared in the form of Superbeings who intend to destroy you and Earth by using your weakness, Krypton. You must move around the screen shooting the beings who throw Krypton at you while avoiding missiles and more Krypton shot upwards from a Ground Control Pod. If you hit a being, Krypton, missile or the Pod then you lose one of three lives. Occasionally the border will turn blue and this means your Girlfriend is falling off a Skyscraper. You must rescue her before she hits the ground.