Automap asteroids

Automap asteroids was supposed to be an Easter egg in the Doom automap display. If completed, it would have reproduced the classic arcade game Asteroids. Dave Taylor started the hack; however, it was never finished.

The Doom source code release contains a list of files which includes a file named "am_oids.c". This is the file which contained the automap asteroids code. However, the file was removed by Bernd Kreimeier who cleaned up the code before its public release.

A copy of the file was recently obtained from John Romero. However, it is clear that the concept was never properly developed. Specifically, the file references functions which do not exist (presumably they were never written) and contains only some basic data structures and simple collision detection code.

Similar implementations
The earlier id Software game Commander Keen 4 which was released before Doom had a Pong easter egg which was actually built in the game.

Catacomb 3-D likewise contained an implementation of the classic Breakout game called "Skull 'n' Bones", although it was not hidden and was available directly from the game's pause menu.