About Commander Keen: Marooned on Mars
Marooned on Mars is the first of the three episodes of Commander Keen in Invasion of the Vorticons, a side-scrolling platform game that Ideas from the Deep developed and Apogee Software published for MS-DOS on December 14, 1990. It was the first set of episodes in the Commander Keen series, and Tom Hall designed it. One point up front: DOS.Zone lists the game as “Commander Keen 1-3”, but only Episode 1 is included.
The hero is Commander Keen, an eight-year-old child genius. Across the three episodes he retrieves the stolen parts of his spaceship from the cities of Mars, stops a newly arrived alien mothership from destroying landmarks on Earth and hunts down the aliens’ leader, the Grand Intellect, on their home planet. Marooned on Mars is the Mars chapter, where it all begins. Throughout, Keen runs, jumps and shoots his way through levels while aliens, robots and other hazards stand in his way. It is a single-player game.
The game was split into three episodes to fit Apogee’s shareware model, in which part of a game was released for free and the rest was sold. Marooned on Mars was the free part. The rights now sit with id Software, part of ZeniMax Media and so of Microsoft.
How it runs in your browser
Press Play and dos.zone opens in a new tab on its “Commander Keen 1-3” page. The site runs the episode inside js-dos, its open-source DOSBox port for the web, which emulates the kind of PC the game was written for. DOS.Zone provides the files, so you don’t install anything or dig out a copy, and no account is involved. No ads appear on DOS.Zone.
Despite the title, the bundle the page loads holds only Episode 1’s program and data, KEEN1.EXE and its .CK1 files, as our check of the file list on 1 November 2026 showed. Players rate the listing 4.1 from 8 reviews. It doesn’t mention saving, so see how progress is kept before a long session.
Controls and devices
Keen is played on the keyboard. DOS.Zone doesn’t list the keys, so check the game’s own screens as it starts, and click inside the emulator window so it receives your key presses.
On a phone, DOS.Zone adds virtual on-screen controls. The game was built for a keyboard and we haven’t tested it on a touchscreen, so a computer is the more comfortable option. Chromebooks haven’t been confirmed.
Who it’s for
It suits anyone who wants to see where the Commander Keen series began, and players who like Apogee’s early shareware games and want one running in a minute without setting up DOSBox. Crystal Caves is another Apogee platformer from 1991, and on DOS.Zone it is also the first episode only. Bio Menace was built on a licensed version of the Commander Keen engine and is freeware.
Is Commander Keen: Marooned on Mars Free, Safe and Official?
Can I play Commander Keen online for free?
Yes. DOS.Zone runs Marooned on Mars, the shareware first episode, free in a browser tab with no account. Apogee released this episode for free and sold the other two.
Does DOS.Zone’s Commander Keen 1-3 include all three episodes?
No. The listing is titled “Commander Keen 1-3”, but when we checked the bundle’s file list on 1 November 2026 it held only Episode 1, Marooned on Mars. Episodes 2 and 3 aren’t included.
Does Commander Keen work on a phone?
DOS.Zone offers virtual on-screen controls for phones, but Keen was made for a keyboard and we haven’t tried it on a touchscreen. A desktop or laptop is the better fit.
