Army Men: Turf Wars on GBA flew under the radar because the Army Men series was over saturated in the market at the time. Two years later, this exact same game engine, right down to the menu interface, was reused to create A Sound Of Thunder, a licensed movie tie-in that really should have never been released (see the link below for my A Sound Of Thunder coverage). In other words, A Sound Of Thunder is the sequel to Army Men Turf Wars as it is more of the same.
This Single-Pak link mode is one of the most technically impressive on the system and is recommended to give it shot if you can link together a full roster of 4 players.
This is Single-Pak link!