Another one that's maybe not really an IF. Okay, it's hardly even a choose your story. In fact, it's just fighting. But it IS fighting crabs!
You pick your battler, then decide how you want to attack the opponent. Some moves and elements are more effective than others and learning the correct combinations is your path to victory! There's no story, no getting involved with characters, but there's fighting crabs, so that kind of makes up for the lack of story if you ask me.
So go fight!