Taking on the role of Duke Nukem, players must fight through 28 levels spread over three chapters (later versions of the game added a further chapter, with an extra 11 levels). As usual for a first-person shooter, players encounter a whole host of different enemies, and can engage them with a range of weaponry. As well as killing aliens to free the Earth, players must also puzzle-solve to progress through the various levels. Some puzzles allow access to extra, hidden levels.
