Proto:Commander Keen Episode 1: Marooned on Mars

This page details one or more prototype versions of Commander Keen Episode 1: Marooned on Mars.

Two prototypes of Commander Keen Episode 1: Marooned on Mars are known to exist, referred to as the "November Beta" and the "December Beta" by KeenWiki.

November Beta

The November Beta is a prototype of Marooned on Mars that was discovered on a Gamer's Edge game sample disk using deleted file recovery tools. This prototype's KEEN1.EXE was last modified on the 20th of November 1990, 24 days before the game's shareware release.

Note that the graphic files (EGAHEAD.CK1, EGALATCH.CK1, EGASPRIT.CK1) and help text file (HELPTEXT.CK1) were not present on the disk, and thus available downloads of the prototype use files from the later December Beta as a substitute.

General Differences

• The executable is not compressed, resulting in the .EXE file clocking in at 78KB instead of the roughly 50KB size later versions have.
• Upon launching the executable, the game does not show a version number or report the detected video card and joystick. The "Decompressing graphics, this may take some time..." line is also absent.
• The game does not end after collecting all 4 ship parts, and the level file (LEVEL81.CK1) used for the ending sequence is completely absent.
• Exiting to the title screen from the overworld does not perform the game over routine (i.e. show the GAME OVER graphic and high score entry), and instead goes immediately to the title screen.
• After picking a save file slot, there is no message confirming the save and explaining how to load the saved game.
• Tank Robot enemies fire their lasers four pixels lower than in later versions.
• The ⇧ Shift + Tab ↹ cheat for walking through uncleared levels on the overworld only requires you to hold Tab ↹.
• God Mode has not been programmed yet.

Intro/Menu Differences

November 20	December 3 onwards

id Software goes uncredited in the Apogee splash screen.

November 20	December 3 onwards

The main menu lacks the "Previews!" option and "Restart Demo" is instead "Resume Demo".

Selecting "Story" on the title menu plays a short animated sequence of a Vorticon stealing the parts of the Bean-with-Bacon Megarocket not present in the later versions, after which the story text is shown. This may have been cut because the cutscene doesn't mean much without the context of the story text explaining the game's premise.

Level Design Differences

Mars Overworld (LEVEL80.CK1)

November 20	December 3 onwards

The second grey city level is mandatory in this prototype, as the overworld lacks a path around it as seen in later versions. The overworld also uses a unique drop shadow tile (tile 101) on the left cliff edges, which was likely removed due wall-adjacent levels causing cutoff and lack of an equivalent tile in the ice areas.

Ice City (LEVEL08.CK1)

November 20	December 3 onwards

The platform with the pizza at the start of the level was shortened one tile in later versions. This was done to mask a bug with the Tank Robot: The extra block causes the robot to not turn around at the platform ledge properly and instead fall off, resulting in the robot hurling itself to watery grave shortly after starting the level.

"Hidden Brick" Hint Shrine (LEVEL12.CK1)

November 20	December 3 onwards

A bunch of solid tiles were added outside the camera border after this prototype to fix a bug where the Yorps could push you outside of the level.

Secret City (LEVEL14.CK1)

November 20	December 3 onwards

The section before the exit is far less rewarding, lacking the pile of teddy bears in favor of a narrow corridor with a Garg plus a Tank Robot on top. This section also has the same issue in Ice City where the Tank Robot falls off the platforms instead of turning around due to the one-tile gap.

Castle (LEVEL16.CK1)

November 20	December 3 onwards

The cans of soda by the hidden "ID" in the top-left corner of the level were originally teddy bears. These were likely changed because the pickups are worth way too many points for a relatively easy-to-find secret.

November 20	December 3 onwards

The arena of the Vorticon guarding the Everclear has some subtle changes:

• The semi-solid platforms are arranged so that the player cannot back out after passing them in this prototype. Out of ammo and wanted to go back for the level's gun pickup? Too bad!
• The passage up to the rope was widened by a tile.
• The ceiling above the Everclear was lowered to prevent the player from accidentally avoiding the pickup.
• Finally, the Everclear itself was moved to the right one tile, likely to make it easier to pick up if the player came from the right instead of shooting the rope.

Text Differences

November 20	December 3 onwards
In war, do not fire all your gleebs in the first ten nooms. Do not waste gleebs.	It is too bad that you cannot read the Standard Galactic Alphabet, human.

The statue in the first shrine originally had a rather nonsensical message that has nothing to do with the game. In later versions, the message formally introduces the series' substitution cypher, the Standard Galactic Alphabet.

November 20	December 3 onwards

The textbox used for the shrine messages is eight pixels thinner than later versions, which causes the hint for hidden platforms to clip outside the box.

November 20	December 3 onwards

The ANSI text screen shown after quitting to DOS is formatted differently.

December Beta

The exact origin of the December Beta is unknown, beyond the fact it was discovered on a peer-to-peer file sharing network. The prototype is dated December 3, 1990 based on the files' last-modified date, a little under two weeks before the game's shareware release.

While the executable does not give a version number upon launching the game, a few sources refer to this prototype as "Version 1.0" due to the earliest version publicly released being labeled Version 1.1.

General Differences

• The startup sequence now reports the detected video card and joystick, but still does not have a version number or the "Decompressing graphics, this may take some time..." message.
• Pressing F8 at any time takes a screenshot and saves it in .PIC format. While this functionality technically exists in Version 1.1, something got horribly broken in the interim and pressing F8 instead causes severe memory corruption. Later versions remove the feature entirely.
• God Mode is now present, but it does not enable no-clipping on the overworld.

Text Differences

The F1 help screen has a few minor text differences:

December 3	Version 1.1
You can move Commander Keen with the joystick, or keyboard.	You can move Commander Keen with the joystick or keyboard.

An unnecessary comma was removed.

December 3	Version 1.1
You can redefine these keys by pressing F4.	You can redefine these keys by pressing F3.

A typo for what key lets you change the controls was corrected.

December 3	Version 1.1
If you use the joystick, use button 1 to jump, button 2 to use the pogo, and both to fire the raygun.	If you use the joystick, press button 1 to jump, button 2 to use the pogo, and both to fire the raygun.

"use button 1" was changed to "press button 1".

Graphics Differences

December 3	Version 1.1

The Vorticon Guard's jumping sprites were redrawn in the final versions.

December 3	Version 1.1

The image preview for The Earth Explodes features a dark nighttime image of the Houses of Parliament in London, rather than the final game's choice of a more immediately recognizable close-up of the Big Ben clock tower. The camera is also higher by a couple pixels.

December 3	Version 1.1

The preview for Keen Must Die!, on the other hand, is completely different, and doesn't bear any obvious resemblance to the final game's levels. The Stuffed Vorticon pickup also hasn't been edited to resemble a VortiNinja yet.