This game is pretty much Guilty Gear XX #Reload with worse graphic (because of the scaling), with a turn button (exactly) and up to 4 players coop play.
The game mechanics themselves are not that bad, what is really bad is that they tried to fit Guilty Gear cast, that we can remember for combos and fast pace gameplay (with cross-ups) into a Super Smash Bros fighter killing Guilty Gear itself. Actually they went even further adding a side-scrolling beat them up mode... like I said before, they totally stripped any "Guilty Gear" from this title.
That said, with much pain you can still get a "normal" arcade mode (1vs1) but there's a curse on that: the turn button. Your character won't turn himself to face the opponent but instead you will turn it when you feel like you feel the need. This is A LOT confusing at start but once you master it allows a few smart tricks you won't be able to do with auto-turn. Still it's definitely totally useless.
Finally a few words about the last boss, remember I-NO from Guity Gear XX? Forget it, you will hit a giant brick in Guilty Gear Isuka, enjoy.
Graphic, as I wrote before, is a little worse than Guilty Gear XX, I mean, visuals are actually better, but since there's a lot of scaling involved, they get worse.
Music instead is good, I liked it more than Guilty Gear XX #Reload in general, I'd say it was because there's a bit of experimentation and less strict 80s power metal (still metal though).
Finally, on this there's no netplay, nor official nor fan made, no one actually cared much about this game. The only reasons you may want to play this game are: playing the new character A.B.A. (which I don't like much actually) and listening to the new tunes that are really good.
So, if you like side-scrolling fighting games like double dragon or such, buy this game and enjoy side-scrolling fighting with Guilty Gear characters, otherwise just buy the soundtrack somewhere and listen to it.