Battletoads & Double Dragon:
The Ultimate Team

Level select:
Press Down, Up(2), Down, A, B(2), A at the player selection screen. Game play will begin with ten lives after a level is selected.

Hint: Extra lives:
Start a two player game and play all the way to the end of level 1-1. Do not enter level 1-2 yet. Instead, turn on player two and use up all of his lives. Continue the game as player two, then repeat this process until all of player two's continues are used. Then, continue the game as player one. However, if all the pods on Level 1-1 were broken, you will have eight more lives and will have earned more through the points awarded while defeating player two. Two more lives can be obtained by going through level 1-1 again.

Five Hearts (Normally 3):
At the Player selection Screen, Hold U + A + B and Press ST to select your character.
(Note: Holding U + A + B and Pressing ST at the Continue Screen will also give you 5 Hearts)