Ninja Gaiden II: The Dark Sword of Chaos

After beating this game and when the final credits is over, at the "THE END" screen, press Right + B + Select. An extra ending sequence will be displayed, which is not in non-Japanese versions of the game.

Near the end of stage 4-2, there's a 1UP. Get it, and then go back up the ladder and out of that area. Return, and the 1UP will be there again. Repeat this process until you have as many lives as you need.

Lighting occasionally illuminates the dark screen in Stage 3-1. Pause the game and wait for the lightning to come.

At the title screen, press and hold Up, Left, A, B & Select (for NTSC games) or Down, Left, A, B, & Select (for European games) and press Start. If done right, a music test with a chibi Ryu will appear. Press Start to exit to the title screen. Now, let the title screen fade to the intro and press Start to go to the title screen again (see title screen twice), press and hold Up, Left, A, B & Select and press Start. If done right, a music test with a chibi Irene will appear. Now for the ultimate music test: press Start to exit to the title screen. Let the title screen fade to the intro, press Start to go to the title screen again, let it fade again and press Start a second time (see title screen three times), now press and hold Up, Left, A, B & Select and press Start. If done right, a music test with channel and volume controls will appear.