There are fifteen different playable characters in all. If you play alone, you'll get to see a funny special sequence about each character after you beaten enough opponents.
Still, the best way to play Smash Face Volley is with another friend on the same computer. Playing multiplayer won't reward you with the special scenes, but it's nice to play against a human since the computer is often way too difficult.
Smash Face Volley is a fun sports game that gives you some of the most entertaining volleyball games you can imagine.