According to the description, if Colossus is already in front, he does extra damage to the enemy, including damage to the enemies in back. That hasn’t always been happening. I understand that if you cast another power before using Colossus’ red, it will prevent the full power from his red. However, I just had a situation where Colossus was in front (from matching red in the prior turn), I did not use any other powers, and Colossus’ red only triggered the minimal damage.