(places you in front of the final boss' door) YNzYSMChriGIgLV-ihOdfCGe
Player Two invincible
Put in regular code for 1st player, enter K x 24 for second player.
Start with a level 45 character
Start game with 1 or 2 players, and pick dungeon you want to play. As soon as game starts, push RUN to bring up password, write it down. Now, cross out characters 10 through 14 and replace with NNNNb. For two player game, cross out characters 34-38, replace with NNNNb. Now reset, enter new password.
Weird codes
When you start any level, get a password. Replace first three to five characters of this code with combinations of x,y,z and other symbols.
Password for 65535 HPs
Enter Player01 or Player02 (all the rest are dashes or plusses)