Keroppi to Keroriinu no Splash Bomb!

Sound Test
Enter the password "さうんと゛をきく" ("Saundo-o kiku", "Listen to Music") at the password screen. Select sound/music with Up or Down, select track with Left or Right play sound with A, stop sound with B. To return back to the game, choose last option and press A.

Rei-kun Minigame
Enter the password "れいくんけ゛えむ" ("Rei-kun gemu", "Rei-kun's Game") at the password screen. Before entering this password, press and hold Up + Left + A + B on the second controller.

The rules are very simple. There are four numbers from 1 to 4, one of them is picked by the computer. You must choose any of three other numbers to gain one point. If you choose the same number picked by the computer, the game ends. Numbers are chosen by the computer based on how much time you need to pick the next one. There is your current score displaying on the screen as well as hi-score (080) for reference.

The game involves no logic or brains, just pure luck and nothing more. Actually, the minigame is so simple, that there is no code for changing the hi-score after you beat it. Even if you beat it, there is no reward for winning it.

Ending Sequence
Enter the password "らすとた゛けみる" ("Rasuto dake miru", "See only the last (scene)") at the password screen.