The PS1 games that don\'t work on PS2 don\'t for the following reason : Sometimes devs do \'shortcuts\' in programming the game
which isn\'t quite conform the way it should. Somehow they get
away with that on PS1 hardware, but since the PS2\'s PS1 game
play-ability requires exact procedure > it doesn\'t work if they made programming shortcuts. So it\'s due lazy/incompotent devs.