Unlock Bruce's Challenges: 
At the Press Start screen, press X, Y, X, Y, X, X, Y, Y, click Left Analog-Stick, click Right Analog-Stick. Alternatiively, beat the game once to unlock Bruce's Challenges. 

Unlock Hard Mode: 
Beat the game once to unlock Hard Mode. 

Ending bonuses:
Successfully complete the game to unlock Bruce's Challenges and Hard mode.

Continue game:
After completing the game, you can play it over again in Hard mode, keeping all the power ups and moves you have earned the first time. You can continue playing the game repeatedly, earning more and more power ups (1000% hits).

Pepsi cans:
When you beat up an enemy you get coins, but sometimes they will drop a Pepsi can. This makes your punches and kicks doubly effective for a short time. In other words, your enemies will go down in one to three blows. You can also find Pepsi cans in hidden crates and boxes.

Infinite dragon Token power: 
Collect 999 dragon tokens