Complete Mission 1 with no continue
Complete Mission 2 with no continue
Complete Mission 3 with no continue
Complete Mission 4 with no continue
Complete Final Mission with no continue
Complete all the missions
Defeat any boss in the game with the METAL SLUG ATTACK
Reach the icy cave's exit with the Elephant Slug
Clear Mission 2 as a zombie
Find and save Hyakutaro Ichimonji
