Commander Keen in Invasion of the Vorticons

Did You Know?

• The game's protagonist, Billy Blaze, puts on his older brother's football helmet to become Commander Keen.
• In the first episode, Keen discovers a Vorticon mothership in orbit after retrieving the final component.

Gameplay

The three episodes form a side-scrolling platform game where the player controls Commander Keen on a two-dimensional plane, moving left and right and jumping. After finding a pogo stick in the first episode, Keen can bounce continuously and jump higher with correct timing. Levels consist of platforms, some of which allow jumping up through them from below. The second episode introduces moving platforms and switches that extend bridges over gaps. Once a level is entered, the only way to exit is to reach the end, and the player cannot save mid-level. Between levels, Keen travels on a two-dimensional map viewed from above, where the player can enter levels or save progress. Some levels are optional or secret. Each episode has a different set of enemies: Martians in the first, robots in the second, and more alien species in the third; all include Vorticons, large blue canine-like aliens. Hazards such as electricity or spikes cause Keen to lose a life if touched, and the game ends when all lives are lost. After finding a raygun in the first episode, Keen can shoot enemies using ammunition; different enemies require varying numbers of shots or are immune. Some enemies, like Yorps, can be stunned by jumping on them. Food items grant points, with an extra life every 20,000 points. Colored keycards unlock parts of levels, and in the third episode an ankh grants temporary invulnerability.

Development

In September 1990, John Carmack, a programmer at Softdisk, developed a method for smooth side-scrolling on IBM-compatible PCs using adaptive tile refresh, which slid the visible screen and redrew only newly visible portions. He discussed the idea with coworker Tom Hall, who encouraged a demo recreating the first level of Super Mario Bros. 3. They did so overnight, with Hall recreating graphics and replacing Mario with Dangerous Dave, while Carmack optimized the code. The next morning, September 20, they showed the resulting game, Dangerous Dave in Copyright Infringement, to John Romero, who recognized the achievement. The scrolling technique required a 16-color EGA graphics processor and did not meet Softdisk's coding guidelines. The team, including Jay Wilbur and Lane Roathe, later approached by Scott Miller of Apogee Software, developed an original game for the Apogee shareware model. Hall designed the three-part game, Carmack and Romero programmed it, Wilbur managed the team, and artist Adrian Carmack helped later. They worked almost three months, often late into the night at Softdisk and at Carmack's home.

Reception

Commander Keen was an immediate hit for Apogee, whose monthly sales had been around US$7,000. By Christmas 1990, sales reached nearly US$30,000, and by June 1991 the game brought in over US$60,000 per month. Scott Miller described it as a little atom bomb to magazine editors and BBS controllers. The success led him to recruit his mother and hire his first employee, and to quit his other job and move Apogee into an office. By 1995 the team estimated the game made US$300,000 to $400,000. Chris Parker of PC Magazine called its release a tremendous success. Apogee announced plans to license the game for a Nintendo Entertainment System port, but no such version was created. Scott Miller estimated in 2009 that the trilogy sold between 50,000 and 60,000 copies. Barry Simon of PC Magazine praised the graphical capabilities as having a Nintendo feel, though the graphics were well drawn but not spectacular in resolution. He noted the game was very fun to play and the scrolling set it apart. PC World termed it one of the most spectacular games available, praising the superb sound and graphics. CQ Amateur Radio described it as Nintendo comes to the PC and the best action/adventure game the reviewer had seen. In October 1992, the Shareware Industry Awards gave the series Best Entertainment Software and Best Overall. Sandy Petersen in Dragon called it one of the best games of its type, praising the humor and not being mindlessly hard.

Legacy

Ideas from the Deep's first royalty check from Apogee in January 1991 for US$10,500 convinced them to leave Softdisk and work full-time on their own ideas. Hall and Wilbur were concerned about being sued, but Romero and John Carmack were dismissive. John Carmack was confronted by Softdisk owner Al Vekovius, who had become suspicious of the group's behavior. Carmack admitted they made Keen with Softdisk computers and planned to leave. Vekovius tried to form a new company in partnership with Softdisk, but other employees threatened to quit if the team was rewarded for stealing. After weeks of negotiation, the Ideas team agreed to produce a series of games for Softdisk, one every two months, and on February 1 founded id Software.