Sonic 3 Codes Level Select You will need a sonic 2 cart for this. Enter level selct for sonic 2 on the sonic 2 cart, and return to the title screen. Now, hold A and press start. As quickly as you can while holding A, remove sonic 2 and put sonic 3 in and press RESET. Now release A at the title screen and press down 2 times. Secret Special Level First enable level select, then enter 1F on music select . After that, highlight stage 2 and press start while holding A.