Perfect
Win a round without receiving any damage in Arcade Mode (any difficulty)

A Small Transformation
Turn small by being attacked (ie, by Amy's+P, etc) in Arcade Mode or Offline Versus

Barrier Destroyer
Destroy all of an opponent's barriers while playing Arcade Mode or Offline Versus

Honey the Cat
Use Honey the Cat in Arcade Mode or Offline Versus (Press START button on Amy and select)

The Enemy Within
Fight a mirror match in Arcade Mode or Offline Versus

Stage 1 Complete
Complete Stage 1 of Arcade Mode (any difficulty)

Stage 2 Complete
Complete Stage 2 of Arcade Mode (any difficulty)

Stage 3 Complete
Complete Stage 3 of Arcade Mode (any difficulty)

Stage 4 Complete
Complete Stage 4 of Arcade Mode (any difficulty)

Stage 5 Complete
Complete Stage 5 of Arcade Mode (any difficulty)

Stage 6 Complete
Complete Stage 6 of Arcade Mode (any difficulty)

Stage 7 Complete
Complete Stage 7 of Arcade Mode (any difficulty)