Bloody Roar: Primal Fury (Game Cube, 2002)

The Bloody Roar series is all about fighters with "zoanthropy", or the ability to turn into human-animal hybrids. As a fight progresses, characters will build up adrenaline based on how much damage they're doing and when their meter is full, they can transform into their hybrid form and (ideally) deal more damage than they can in their human form. This system definitely adds an interesting new dimension to the basic fighting game formula since the player often has to fight in a different style based on what form they're in. There are also plenty of characters, including some which can be unlocked by progressing through the game, and plenty of different animals to transform into (including the unlockable PENGUIN fighter... I guess they ran out of fierce creatures).
Unfortunately, despite its promising concept, Bloody Roar 3 lacks the depth of other fighters available on the GameCube. You would think that the elephant man would move slower but do more damage and the cat girl would be quick with less powerful strikes; but generally speaking, there's not much difference between the way the characters fight. The story mode is also a little weak... you'll fight a series of battles with little explanation and little increase in difficulty, only to be rewarded with an anime cut-scene ending that's usually pretty cryptic. The music is pretty generic as well, and seems out of place in a fighting game, in my opinion. Put this game next to Soul Calibur II and Bloody Roar 3 just doesn't stack up, animals and all.
That's not to say the game can't be fun, though. It is kind of a gimmick game but the gimmick they came up with is well-executed. If you enjoyed the Street Fighter series, which has many similiarities in control with the Bloody Roar series, or if you like the 3D Mortal Kombat games, which offer a similar gameplay feel, you'll probably have fun with Bloody Roar 3. Just don't expect to find a diamond in the rough in the bargain bin with it.