Here is a list of the assist trophies in the game and how they are unlocked.

  • Barbara - Unlock 25 songs
  • Custom Robo - Fight in 100 Brawls
  • Gray Fox - Unlock Snake
  • Infantry & Tanks - Fight in 300 Brawls
  • Issac - Fight in 200 Brawls
  • Shadow the Hedgehog - Unlock Sonic