Ride all the Slugs
Complete Final Mission with no continue
Complete all the missions
Play all the routes
Achieve over 3,000,000 points
Complete Mission 4 with no continue
Find and save Hyakutaro Ichimonji
Complete Mission 3 with no continue
Clear Mission 2 as a zombie
Complete Mission 2 with no continue
Reach the icy cave's exit with the Elephant Slug
Defeat any boss in the game with the METAL SLUG ATTACK
Complete Mission 1 with no continue
Start Mission 1