Bomberman 64: The Second Attack! Cheats

First, a Red Cup (received when challenge 5 is completed) must be obtained in each of the five battle modes. This will unlock the first secret option, which allows you to play as computer characters in battle.

Now, on the character select screen in battle mode, hold down Z and press A. You can now choose to be any of the computer characters.

You can unlock a different look for the salesman in the Merchant Ship Frontier. First, you must unlock the four "cowboy parts" in the shop by buying all the other parts (Not hints, the etc. items, or the parts found in the stages) from the shop first. Buy the four cowboy parts after they are unlocked, and the salesman will look different from now on in the save file this was accomplished on.

Note: You cannot change the salesman back after you do this. If you don't like the new look, don't buy all the parts.