Successfully complete the game to unlock the "Concept Art Gallery" option at the main menu.
Double Dragon difficulty
Successfully complete the game under the Dragon difficulty setting.
Dragon difficulty
Successfully complete the game under the Normal difficulty setting.
Fuzz Face
Set Fuzz Face free by dodging seven times between the two tombstones next to the ladder in level 6, "Assault Zone". Fuzz Face will now follow you and drop Dragon Kick and batteries occasionally.
Hidden area
Play the last level. After becoming a Ro-Bro, move to the left until reaching the left side of the screen, the move down. You will descend a hidden ladder and find an area with extra lives and two chests.
Play as a Ro-Bro
While on the stage select/map screen, press L1, L2, L3, R1, R2, R3, Select and Start at the same time to play as a Ro-Bro. Input the code again on the same screen to revert back to normal.
Secret level
Play level 7, "Some Kind Of Lab". Punch the heavy bag in the glass cell where you start 87 times until a chime sounds. After a few seconds and your head and others will be replaced with Yoshihisa Kishimoto's face.
Various Trophies
Complete the following tasks to unlock PlayStation 3 trophy rewards.
Trophy
How to unlock
A Foot Face? (Bronze)
Become the hidden idol!
Double Dragon (Silver)
Finish every stage cooperatively on Double Dragon difficulty with friendly fire enabled!
FuzzFace!! (Bronze)
Befriend everyone's most favoritest helpful character!
Gleam On! (Bronze)
Dodge and get the Gleam 50 times.
Max Fidelity (Gold)
Max out every song to level 50!!
Metal Head (Bronze)
Upgrade a song at the Tapesmith.
Misters Perfect (Silver)
Complete any level in co-op without taking any damage... with friendly fire enabled!
Mr. Perfect (Bronze)
Complete any level without taking damage.
Pick a Winner! (Bronze)
Nail all enemies with the hair pick.
Single Dragon (Silver)
Finish every stage solo on Double Dragon difficulty!
This Channel Sucks (Bronze)
Break all the Skullmageddon monitors in the Rocket Dojo.
Concept Art Gallery...