I played the PC CGA version... boy, do I hate that cyan/magenta/white combination. My version was not able to save the state... I started one early afternoon from level 1, I was defeated at level... 139 I think, at late night after possibly 9 hours of playing. Levels were quite well designed, and we are talking about 150 of them here: the designers (there is some story on the internet about them) squeezed the game mechanics and also the bugs of the AI to make the levels interesting.