Complete the indicated task to unlock the achievement.

Achievement	How to unlock
Big Man With a Big Problem	Defeat Big Man.
EXTREME!!!	Defeat Extremity.
High Roller	Defeat Roller Derby.
I Know What You're Thinking	Defeat Medatsu the Mystic.
Kill the Superweapon	Beat the Game.
Reptile Brain	Defeat Varanus the Lizardman.