Duke Nukem is a 1991 platform game developed and published by Apogee Software for MS-DOS. The 2D, multidirectional scrolling game follows the adventures of fictional character Duke Nukem across three episodes of ten levels each. The name was briefly changed to Duke Nukum to avoid copyright issues. Duke Nukem was followed by the similarly-styled Duke Nukem II, in 1993. The series made the jump to 3D graphics with Duke Nukem 3D in 1996, which became the most popular of the three games. Gameplay The main objective of the game is to get to the exit of each level, while destroying enemies and collecting points. Many objects onscreen can be shot including boxes, obstacles and blocks. Besides points, some collectibles include health powerups, gun powerups, and some inventory items with special abilities. The final level of each episode has no exit, and is instead completed by finding and defeating Dr. Proton. At the end of every level (with the exception of the last level in each episode), the player can receive up to seven 10,000 point bonuses, earned by making certain achievements in the level, such as destroying all cameras. Plot The game is set in the year 1997. Dr. Proton is a madman, determined to take over the world with his army of Techbots. Duke Nukem, the eponymous hero, takes upon the task of stopping him. The first episode takes place in the devastated city of Los Angeles. In the second episode, Duke chases Dr. Proton to his secret moonbase. In the third episode, Dr. Proton escapes into the future, and Duke pursues him through time, to put an end to his mad schemes. Development According to programmer and co-creator Todd Replogle, John Carmack helped him program some low-level parts of the game code in assembly language. The game world scrolls by shifting 8x8 "blocks" rather than individual pixels. The game's original title was Heavy Metal, but producer Scott Miller hated the name and chose to name it after the lead character, similar to comic books. He proposed Duke, which he felt sounded strong, and Replogle proposed Nukem as his last name. Legal concerns with the game name After the game's release, Apogee Software became aware that the Captain Planet and the Planeteers animated series featured a character with the same name (Duke Nukem) and therefore to avoid a lawsuit, the software house renamed the 2.0 version of its game