You need two controllers to pull this off. During gameplay, insert a controller into port 2, then take it out without doing anything else.
On the controller in port 1, immediately press X, X, Y, Y, B, B, A, A. A sound will confirm that the code was entered correctly.
Once in Cheat Mode, press X, Y, A, B, X, Y. If the code was entered correctly, your health bar will be yellow.
Once in Cheat Mode, Press L3, L3, R3, R3, L3, L3, R3, R3. You can enter this repeatedly for the endless cash.
Enter [email protected]& as your Player name. Then start a new game for the level select.
Have a controller in port one only, press L, L3, R3, A, B, R, B, A, R3, L3, L. Then, insert a controller into port four and remove it without doing anything else. Repeat the code to disable it.
Thanks to Revolution reader pooofs, DerekM89!