There was an interesting write up in 2013 of someone who reverse engineered the game to develop a fix for the main flaws in the gameplay:

http://hackaday.com/2013/04/06/fixing-the-worst-video-game-e...

It's quite an interesting read and exposes some of the concerns that must have been present in designing games for incredibly limited memory at the time, including where to put the patched instructions.