Repton is a Defender-inspired scrolling shooter written by Dan Thompson and Andy Kaluzniacki for the Apple II and published by Sirius Software in 1983.

The player controls a fighter ship sent to stop a fleet of invading aliens from building an attack base on the planet Repton.

"Warning" messages indicate that a fresh wave of enemies is arriving, while an "Alert" tells of an attempt to siphon energy from the planet.

Once the base is completed, the planet's defenses trigger a bomb that destroys the entire surface and the action shifts to the caverns, where the radar does not function.

Here, the player must dodge enemy attacks and eventually destroy the base's power core, after which the next level begins with increased difficulty.