Just played the genesis version and would recommend to stay away from it if you have or can get other versions. The graphics are good but there so much slowdown I felt it there was no fluid movement and had bad playability. After 10 minutes wanted no more of it. The good thing is the controls are pretty responsive and be sure to use a six button controller which has the strong attacks on the C and Z buttons, makes things easier and more natural for the ones new to the series. The manual covers all of the moves of each character and they seem to be all there.
I'm comparing it to the psp neo geo arcade vol which should be an almost exact port and I'm running it on an actual genesis, maybe on an emulator the slowdown could be reduced.
Btw you can change the difficulty on psp for each game but you have to do it before you start each one. Still on easy haven't reached the boss, the comp gets relentless when you lower its health bar and the count reaches the 20-15 second mark. Have to be less agressive and use more counter attacks. Tonight I'm trying out the Sega CD and 3DO versions, let you know about it later.
To finish up my previous post and since there is another game starting, my sega cd just died but I managed to check out the 3DO version which has almost everything the arcade version has. Nothing to complain there is just a quick loading before the start of a fight and the panasonic standard controller responded very well in spite of it being one of the worst controllers I've used (Kicking is done holding down the R button). Sound effects and music gets an A even using headphones through the controller. This should have been amazing back in those days, well so was a neo geo aes. Well onto Lunar then...
I always wanted to buy the Japan only PS2 version. Its like a remix version with a bunch of characters. I can't remember the name. Theres something like 60 characters to choose from. The backgrounds looked really clean. It has te same old sprites though. SS needs a HD rehaul similar to Street Fighter. That would be really fucking awesome.