http://www.gamefaqs.com/dreamcast/913699-street-fighter-iii-3rd-strike/faqs/8138"System Direction" is an interesting feature that lets you change the basics of how the game plays. For example, you could disable high jumps, or make EX moves cost nothing to use, or even change the Leap Attack command back to d,d + P / K instead of MP + MK.
This FAQ lists all the different ways the mechanics can be altered with the "System Direction" feature in the DC, PS2, and XBOX ports. Remember all those people complaining about parrying? Well, you can do things like make the timing more strict, remove "guard parrying," or remove every type of parry altogether. You can turn the game into Street Fighter Zero by adding air blocking and access to all Super Arts, or turn it into Vampire by adding chain combos. You can remove a lot of features and have a visually superior Champion Edition-like game. If you go all out on the move cancelling you can end up with something resembling the Marvel series, as demonstrated in these combo videos:
Part 1:
http://www.youtube.com/watch?v=VPQrtT5zuIIPart 2:
http://www.youtube.com/watch?v=xXXMFgrHNMMThis is a fucking amazing feature and should be a standard feature for all fighting games on a console. Third Strike could still be a tournament standard, but for whatever reason organizers haven't had any tournaments with alterations like disabling parrying when it's as simple as moving a few spaces on the main menu. It's not like they're playing the CPS3 version, in most cases.