Proto:Mighty Mighty Missile!

Mighty Mighty Missile! began as a homebrew project on the Genesis, originally being developed under the lawyer-baiting title ChuChu Rocket! It later transitioned to a commercial game on the Sega CD. Prerelease builds from both periods have been released.

ChuChu Rocket!
This early Genesis version has just one playable stage; it's followed by a second, played by the CPU, after which the game restarts. Notably, this game uses the ChuChu Rocket! title screen rather than the version in the later demo and commercial game.

CGE 2004 Demo
A close-to-final build was created for the 2004 Classic Gaming Expo and later published in its unfinished state by Older Games. The completed game was eventually released by Good Deal Games.

Genesis Build
While this demo was aimed at the Sega CD, included on the disc (/BONUS/MMM.BIN) is a largely identical version built for the Genesis. The only major difference is that this version lacks the CD audio of the Sega CD demo. This build was also included on the final disc.

Images
Along with the Genesis build in /BONUS are some box art and company logos. It's worth mentioning that Older Games, as seen in one logo and on this early boxart, did not ultimately publish the final game.

Credits
In the final game, the credits display after completing all 96 puzzles (or via the options menu, which is not available in the demo). In the demo, the credits display after completing the 24 "Normal" puzzles. After the credits, the demo version restarts and players are able to select the first "Hard" puzzle, which will again display the credits upon completion. No further puzzles are able to be selected.

The demo's credits consist only of the "Special Thanks" portion of the final credits. These are slightly different to the final version. In addition, the post-credits gag in which a group of Mousers who accompanied the credits are woken and run away is unfinished in the demo, with the game misinterpreting the data after the credits in the ISO as additional, heavily glitched credits.