Battle Arena:
To unlock the Battle Arena, get all the grades. You should then get the Master grade. The Battle Arena will now be open in Robot Beach.
Burningundam3241.

Hint: Defeating Malakai:
In the first part (where there is lava for a field), keep a steady pace while jumping around on the stones. Hold [Forward]

OUR RATING FOR THIS GAME: 

(5 is best)