If you started with one of the Calibur series, be prepared for an adjustment
The control is probably the most-intact link between Soul Blade and the Soul Calibur series. You can connect some characters to their Calibur counterparts easily, although there are quite a few differences. The option to strike a player while they're down is useful in Soul Blade, but more of an annoyance than anything. The only major problem, wheras the players in Calibur move with intense speed after you've entered a command, the movements in Soul Blade are very sluggish in comparison; this is what will more than likely present the most difficulty if you started with one of the Calibur games. The fact that the computer seems to be able to control the characters better than you will more than likely be the cause of many defeats.
Sound-wise, Soul Blade is it's own game. The music and sounds of the Calibur series are somewhat more better suited for the game. While I must admit, the music that plays to the actual fighting isn't particulary enjoyable nor suitable for a fight, the music for the rest of the game is somewhat addicting. The game's intro music "Edge of Soul" is a very addicting song for some reason, I feel there could not have been a better song to play alongside the movie. One interesting note of Soul Blade however, is the voice overs. In the Calibur series, SC1 had pure japanese, SC2 had the choice of english or japanese, and SCIII has the same choice. However, in Soul Blade, the voices were done based on the nationality of the character selected. If one chose an asian character such as Hwang or Taki, they would speak in japanese. However, if one chose a player of any other nationality, such as Cervantes, Siegfried or Sophitia, they would speak english.
Graphics for Soul Blade are pretty much what I expected from an early Playstation game. The intro movie is a crystal-clear masterpiece of the Playstation, and I feel I would buy the game simply to watch it. Gameplay wise, think somewhere between Tekken 2 and Tekken 3... just a bit slower. The camera will at times move in the most inconvient places, and sometimes go right through a character showing breakdown. Once you get past the old-age graphics however, you don't tend to notice them as much.
Gameplay-wise, the game is relatively simple, defeat an opponent by either depleting their life bar or knocking them out of the ring. In this game only, it is possible to actually knock a character's weapon out of their hand, after which they would fight in a boxing-like style. If you've played any of the Calibur games, you should be familiar with the rest of the game.
In the end, while it is a difficult game, once you've grown used to it, the problems wil all simply vanish, and you're left with a fun, enjoyable game.