In the early 80's programmers had to write a number of different versions since no platform was pre-eminent. There were Atari 800, C64, Apple, Mac and IBM PC versions of games, but because of the specific constraints of each systems, the games were not all the same. Some games were horrific excuses of a translation. One can argue that all of the games on older systems, Atari 2600 being the main culprit, made horrendous version of the arcade original. Ok, I can entertain that argument, but some were so disappointing that they deserve special mention here.