The Gameboy Color version of Side Pocket features two link cable multiplayer modes.

9-Ball is straightforward 9-Ball that probably would have been better implemented as a pass-the-Gameboy hotseat option.

However, the Pocket mode is much more exciting. When a player sinks a ball, that pocket becomes blocked on the opponent’s table. This essentially turns gameplay into a tug-of-war mixed with a race-to-the-finish. Honestly, it is the best mode on the cartridge and (I think) is an exclusive feature of the Gameboy version. The Game Gear version only had linked 9-Ball.