With this game, Sega is trying to emulate what Nintendo did with Super Smash Bros. Which is fair enough when you consider the depth of history and the number of trademarked characters Sega has at its disposal. Unfortunately, whereas Super Smash Bro's was a relatively unique concept, this, in essence, is nothing more than a stripped down version of Virtua Tennis (a game that is also made by Sega).
That's not to say that this game doesn't have its good points. Virtua Tennis is a fantastic game to build off of, and the tennis gameplay itself is very commendable, if a little simplistic at times. The characters, tennis courts and music are very faithful to the gaming franchises included and it's that what makes it an absolute pleasure to play. Wether you're a Super Monkey Ball, Samba De Amigo, OutRun, ChuChu Rocket or a good old regular Sonic lover, there's something for every kind of Sega fan here.
Where this game truly shines however is in the mini games. These mix tennis with the gameplay from the franchises on which the area is based. For instance, in the Virtua Squad minigame, you shoot a tennis ball at the bad guys that pop up, just as you did on the original. In ChuChu Rocket, you lead a line of mice to their rockets by changing the direction arrows by aiming tennis balls at them. You can see where I'm going here. The only problem with this is that you've got to actually be familiar with the original games to really understand the concept of the gameplay involved. But this is just me being picky. Most Sega games are relatively simple in nature, so I don't think it'll take you too long to work out. Overall though, these minigames are a great and creative addition to what would have been a rather bland tennis game.
As far as character-themed compilation games go, the value of this game is wonderful. It'll keep you busy for hours with it's reasonably well balanced AI, it's range of mini games and the usual single player and multiplayer modes. The only downside is there's no online play, but hey, I can live with that.
So if you want an easy to pick up game that'll heavily tinker with your sense of gaming nostalgia, you can't go far wrong with Sega Superstars Tennis.