On The level select screen press LT,LB, click the left stick RT,RB click the right stick then press back and start at the same time, if done correctly you will hear a sound and when you start a level you will be ro-bro.

The harder the difficulty, the higher the drops from enemies

Complete the game once and the Concept Art Gallery will unlock on the main menu, with 97 pages of unused concepts, drawings, and early game screenshots.

To use in for your Xbox Live profile

In Stage 7, "Some kind of lab", you will start out right next to a punching bag. Attack the bag EXACTLY 87 times (1987 being the year Double Dragon came out) and you will hear a chime indicating you unlocked something. Immediately stop and the game will teleport you to a different area of the stage full of enemies, traps, and platforms. As an added easter egg, every character, including the Lee brothers, all have Yoshihisa Kishimoto's face instead of their normal face. He is the one that developed and made the original Double Dragon. As soon as you complete the area, the secret achievement "A Foot Face?" (5) will unlock.

Complete each achievement to get the allotted gamerscore.

On the very last stage of the game, after becoming a Ro-Bro, head left. Eventually, you will reach the left side of the screen. When you do, head down. You will climb down a hidden ladder with multiple 1-ups, and two unlockable chests.

On stage 6 "Assault Zone", after the Hellacopter section and right before the first ladder, there are two gravestones sitting on the bottom of the screen. Go between them and press the dodge button 7 times and it will unlock "Fuzzface", a strange and out of place creature that can fly and talk. He'll hover over you for the rest of the game and occasionally give you power ups and items, making the game much easier.