I've had BBA working on this game, but only when running two dolphin instances on the same computer. Even once you get the game instances to see each other, the game requires really low network latency, and dolphin's current implementation (based on openvpn TAP) just can't cope with this.
Edit: To be more clear, the game essentially works how dolphin's netplay does: it broadcasts sampled gamepad input data each time it is polled from the hardware. However, dolphin cannot manage this connection at a high level, so the game's code must deal with any synchronization differences between each "gamecube" in the game. As it happens, the game's code includes NO error correction for stuff like that, so it breaks as soon as dolphin instances go out of sync (where sync includes network transmit).
Edit: To be more clear, the game essentially works how dolphin's netplay does: it broadcasts sampled gamepad input data each time it is polled from the hardware. However, dolphin cannot manage this connection at a high level, so the game's code must deal with any synchronization differences between each "gamecube" in the game. As it happens, the game's code includes NO error correction for stuff like that, so it breaks as soon as dolphin instances go out of sync (where sync includes network transmit).