Contra (NES)/Secrets

30 extra lives
At the title screen, enter the following combination:

,, , , , , , , ,

Then to begin a one player game, press, or to begin a two player game, press ,.

Sound test (Famicom version only)
At the title screen, press and hold the buttons simultaneously and push.

Secret ending (Famicom version only)
During the ending, before the closing credits starts rolling, press and hold and keep on holding until the credits are over. If done correctly, you will receive a message from Red Falcon, vowing his revenge.