Commander Keen in Invasion of the Vorticons
1. "Marooned on Mars" (first released as shareware on December 14, 1990)
While Commander Keen is exploring Mars, the Vorticon steal four vital components of his ship and hide them in Martian cities, each guarded by a Vorticon soldier. In this episode, Keen acquires his trademark pogo stick and meets a variety of Martian aliens and robots.
2. "The Earth Explodes"
Keen returns to Earth only to find the Vorticon mothership hovering above with its deadly X-14 Tantalus Ray cannons locked on to eight of Earth's greatest landmarks: the Big Ben (London), the Sphinx (Cairo), the Sydney Opera House (Sydney), the Statue of Liberty (New York), the Eiffel Tower (Paris), the Colosseum (Rome), St Basil's Cathedral (Moscow), and the White House (Washington D.C.). Keen has to find and deactivate each of the cannons to save Earth. Unlike the first game which had a happy and friendly atmosphere, almost everything in this game is hostile towards Keen, from the floating machine gun robots to the electrified floors. The engine has more features than the first episode, such as light switches and moving platforms.
3. "Keen Must Die!"
Keen travels to the Vorticon homeworld in search of the mysterious Grand Intellect that has directed the Vorticons toward Earth. The game features the cities, parks, and suburbs of the Vorticons, and their women, children, pets, and mechanical toys make up the enemies. The Vorticon alphabet is also decoded in a school house, allowing for the player to travel to the other in-game locations and read the Vorticon signs.
[edit] Keen Dreams
3.5. "Keen Dreams" aka "The Lost Episode" (published as shareware by Softdisk)
After refusing to eat his vegetables, Billy is sent to bed by his parents. He falls asleep, only to awaken in a strange vegetable kingdom led by the evil potato king Boobus Tuber, who has imprisoned other sleeping children there. In the dream world, Keen does not have his trademark raygun and pogo stick, but has to defend himself with "Flower Power" seeds that temporarily turn enemies into flowers.
[edit] Commander Keen in Goodbye, Galaxy!
4. "Secret of the Oracle" (first released as shareware on December 15, 1991)
Keen's newly finished homemade faster-than-light radio picks up a plot by the Shikadi to destroy the galaxy. He rushes to the planet Gnosticus IV to consult the Keepers of the Oracle, but discovers that they have been taken captive. Thus, the gameplay centers on Keen finding and rescuing the eight elders. This episode features huge levels and a wide variety of enemies, such as rocks that only move when Keen's back is turned, and modified game mechanics. The game also features a mini-game called "Paddle War", a remake of the video game Pong, though this version is vertical instead of horizontal.
5. "The Armageddon Machine"
After getting information from the Oracle, Keen lands on a massive Shikadi space station, the Omegamatic, nicknamed the Armageddon Machine, and seeks out the mysterious Gannalech. The gameplay centers on Keen advancing through the Omegamatic to deactivate it.
[edit] Commander Keen in Aliens Ate My Babysitter!
6. "Aliens Ate My Babysitter!" (published commercially only by FormGen, Apogee resold it as a retailer; now discontinued)
When Keen's babysitter Molly is abducted by the Bloogs, Keen must come to her rescue by fighting his way through the inhabitants of the planet Fribbulus Xax. This is the last episode of the original Keen series.
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