I'm going to agree with the above poster and say that neo4all is absolutely the best thing to happen to the Dreamcast in years. I am a long-time fighting game fan who simply never could afford the NeoGeo MVS system and its $250+ carts, and didn't want to deal with the 30 sec+ load times of the NeoCD. Finally, there is a decent platform to experience these awesome games. My sincerest of thanks to the author of this absolutely amazing piece of software, your hard work is very much appreciated.
And although I'm not technically inclined, I can offer a few observation notes regarding the games I've tested on neo4all beta 2, if it helps at all. All assume frameskip = auto; 68K = normal; Z80 = under (default settings):
OVERALL: Speed seems increased slightly over the original system. However, this is a GOOD thing for me, as most of the old-school fighters could use a speed boost to keep up these days. (Samurai Shodown II Turbo!! Awesome!!) Haven't tried over/underclocking 68K.
SAMURAI SHODOWN 1/2/3/4: All run perfectly, albeit at the increased speed. Background animations seem particularly accelerated.
FATAL FURY: Can't get this one to boot.
FATAL FURY SPECIAL: No known issues.
REAL BOUT FATAL FURY 1/2/SPECIAL: All perfect (Real Bout 2 is a great game!).
ART OF FIGHTING:Can't get this one to boot.
ART OF FIGHTING 2: Animation/frame rate seems choppy, but this may be the way the game actually plays. Can't remember.
ART OF FIGHTING 3:Can't get this one to boot. May be a disc issue.
KING OF FIGHTERS 94/95/96/96 COLLECTION: No known issues.
NEO GEO CD SPECIAL: Crashes in several areas.
ADK WORLD: No known issues.
KARNOV'S REVENGE: Perfect except fot the above noted background glitches (the floor layer moves with the fighters!).
SAVAGE REIGN: No known issues.
AGGRESSORS OF DARK KOMBAT: No known issues.
RAGNAGARD: No known issues.
WORLD HEROES PERFECT: Awesome, but CDDA sometimes drops out and doesn't come back. Maybe a disc defect.
BTW, to the above poster, the background music you're referring to is probably the CDDA, and yes, it should work with the beta 2 release (it does with all of my games).
Again, to the author, thanks a ton for this great software, and if there's anything I can do to aid in the testing and development of neo4all, please ask.