Don't waste time and money on this title, GG is a great series, this game... is not, lots of better fighters out there.
I'm getting ahead of myself, let's start from the beginning:
Guilty Gear, the title that started the series, crazy game with an insane combo system, blah blah blah, you heard it all before, yes it's true, this game has characters that are completely nuts and that makes them that much more unique, the fighting system is nice and easy to pick up, but there is the first problem, the manual teaches you nothing on how to play, how to execute destroy moves and such,
and that's the first fault.
The second fault has to be the fact that the AI is incredibly stupid in the first 6 or 7 stages and gets incredibly hard and cheap from the 8th onwards, and it's not a challenging AI either, it's just cheap and annoying, you actually end up having to use some other cheap and annoying strategy to win, spamming moves is your best friend here, and by that I mean repeatedly pressing the punch button to score a 4 or 5 hit combo, that takes away the freedom of playing the way you like, also some of the moves at your disposal are just useless and you'll end up never using them, that goes for all characters.
The Option menu is a joke, you can't really opt for anything, can't change difficulty, can 't change number of rounds, endings are not saved anywhere to re-watch later, there is just not enough reasons to play this game at all.
Bottom line: Guilty Gear is a cheap game and if you are nuts about GG then by all means add it to your collection, I got it for $8.95 on the australian playstation store, otherwise don't bother, try the later installments of this series or just move to other 2D fighters, there is a lot of them out there and watching my character getting overwhelmed by combos while I can't even counter cause of the degenerated fighting engine in this game made me realize just that.
It's nice, it's flashy, it's crazy, it's just not worth it though.