If all you have is a Wii-mote, then back off. Otherwise, step right in.
The next thing players wil notice is the incredibly odd character line-up. While there are characters that seem ordinary (for a game) such as a wealthy-looking vampire, a ninja, a pirate and a guy with a big sword, there are far more strange (for lack of a better term) characters. There's a really tall guy who wears a paper bag on his head, another guy with his hair covering his face who uses a snooker cue and balls as his weapon, a nun who fights with a yo-yo who is actually a guy and a zombie-like woman whose weapon is a talking key that's larger than her. Then of course there's a large number of 'is this a guy or a girl' characters, as comes with the odd line-up.
The gameplay is more complex than anything I've seen in a fighter: It has 3 battle systems, unlockable original character versions (where they have the movesets from a previous game in the series) a tension bar, a Burst gauge plus some exceptions, one of which is a robot that has a temperature(?) gauge. Each character is unique in their style and attacks yet the roster manages to maintain balance. The plays in the style of an arcade fighter with the 5 attack buttons: Punch, Kick, Slash, Heavy Slash and Dust. There is also a a taunt button. However, the wii remote controls suck. Where it deserving of elaboration I would cover a page in how terribly abysmal the wii remote controls are. If you do not own a gamecube or classic controller, do not get this game as you will not enjoy it. That's all I will say on that matter, but don't ignore it, they really do completely and utterly suck. Moving on:
Combos are easily performed, but not to the extent that they can be thrown out without any practice. Despite this they can be difficult to remember which means you can still destroy your friends who have only had a few minutes with the game. Although, it doesn't take long to unleash some lengthy, flashy combos. There are even finisher moves as well as super combos in order to 'spice things up a little bit'.
The graphics are... not what I expected, but I had forgot that it was an arcade game so taking that into account they are perfectly suitable. The sprites are high quality and the backgrounds are well made. The effects such as slashes are contrasted nicely against the backgrounds making it even more satisfying to unleash your attacks. Presentation on the whole is amazing. If you can keep the pace up with attack, then the music and the graphics will do the rest.
The Guilty Gear series seems to have an intricate story, yet so far I have not seen anything that can tell me what's going on other than the interactions between character's at victories and about 2 frames in the opening which took a few watches to finish reading the 6 letters on the screen. There does seem to be plenty of unlockables including videos which may shed some light on the matter.
Other than that, the only problem I can think of (ignoring the pathetic wiimote controls) is the translation, the character interactions, other than a small passage after you defeat or are defeated by your opponent, are in japanese without subtitles. This means you feel like you are missing information which you could use to piece together the story, or at least the characters' personality.
Overall, Guilty Gear XX Accent Core is the most enjoyable fighter I have ever played but I think a lot of people will be put off by the madness and weird-ness of it. Again, if all you have is a wiimote, do not buy this game, otherwise it is worth the small price it is now. And that's a complete bargain too.