Virtua Fighter series... Each character has a ton of combos and when adding in countering and blocking mixed in with each character's specific fighting style, it takes a long time to master one player. Years ago (saturn VF2), I kept a notebook of every player and spent time mastering one by one. I had 4 down cold with one real standout -- Sarah. It was amazing when a relative noob played me -- quite embarrassing for them... I've played MANY fighting games from 2D streetfighter through today's VF5 and I just haven't seen anything quite as difficult to master. Just one person's opinion, though...