Press LS, RS(2), LS, RS, LS(9), RS, LS(6), RS, LS(4), RS at the options screen (with Gir Draxon's face displayed). Gir Draxon's eyes will glow red and the word "Cheater" will appear to confirm correct code entry. The Boss will appear after the first wave of enemies is destroyed. During the game, pressing LS will restore shields, holding LS will make the Raven invincible, and RS will stop enemies.