What is the secret code for arcade mode?

Please provide more context! I need to know what game you are referring to in order to help you with the secret code for arcade mode.

For example, tell me:

* What game are you playing? (e.g., Street Fighter, Mortal Kombat, Pac-Man, etc.)

* Is this a specific version of the game? (e.g., Street Fighter II: Hyper Fighting, Mortal Kombat 3, etc.)

* What platform are you playing on? (e.g., arcade cabinet, home console, PC, etc.)

Once you give me this information, I can hopefully help you find the secret code.