>>43202634There's actually a lot of cards they didn't know how to program and thus left out. Evidently most things involving counters were a struggle. They managed to do Hungry Snorlax, though.
At least in GB2 they included a decently large amount of game-exclusive cards, some of which are even decent like GR's Mewtwo, Dark Venusaur and Dark Clefable. I actually made a pretty solid spread deck in GB2 based around Dark Ivysaur.