Play Red Rabbit Kotomi: Before pressing START, hold B. Then hold START too until the selection screen appears. Then press DOWN four times: the first when the counter reaches 7, then 5, then 2, and the fourth time when it reaches 0.

Play Diabloon: Before pressing START, hold B. Then hold START too until the selection screen appears. Then press RIGHT once, then DOWN four times: the first when the counter reaches 7, then 5, then 2, and the fourth time when it reaches 0.