Duke Nukem 3D
Taking on the role of Duke Nukem, an imperious action hero from Earth, players must fight through 28 levels spread over three chapters. A commercial upgrade, called The Plutonium Pak, later added a fourth episode of 11 additional levels, some new enemies, and one new modified weapon. As usual for a first-person shooter, players encounter a whole host of different enemies, and can engage them with a range of weaponry.
Duke Nukem 3D is set "sometime in the early 21st century" in a broken and far more morally corrupt Los Angeles, and expands to locations such as lunar space stations. Through cutscenes and gameplay, the premise is that an alien transgenic species has infiltrated Earth in light of Duke's absence while fighting in space. Upon crash landing back to Earth, Duke finds most humans are absent, with few attractive women remaining as diversions for the aliens. American civilization has been reduced to a virtual wasteland while pornography has become the sole source of entertainment. As well as killing aliens to free the Earth (and more specifically, retrieve "babes" that have been kidnapped), players must also solve puzzles to progress through the various levels. Some puzzles allow access to extra, hidden levels.