Beyblade Metal Fusion isn't a bad game; it's an outright horrible game. It's playable, but because the whole thing is a repetitious mess, there's no way anyone would want to play more than a single battle.
Battle Fortress ultimately stumbles in the same way as the portable Metal Fusion, though, with a core gameplay system that's too limited to keep your interest for more than a minute or two and control issues that make it frustrating to play for even that long.
Overall, Beyblade: Metal Fusion is a big disappointment for me. The extremely ridiculous storyline is just uninspired, and the battles get monotonous. Fans of the franchise may gain something out of it, but everyone else should stay away.