Original: However, the DS consoles do not have a GBA game link connector, and so can not play multiplayer GBA games (except for the few that are multiplayer on a single GBA) or link to the Nintendo GameCube. The DS is not backward-compatible with Game Paks for the original Game Boy or the Game Boy Color.
Simplified: It can play Game Boy and Game Boy Color games, along with the new cartridges introduced with the GBA.