Metal Slug Anthology (Wii)

Desktops 1
Successfully complete all seven Metal Slug games on the Normal difficulty setting with limited continues to unlock the Desktops 1.

Desktops 2 and Special Music
Successfully complete all seven Metal Slug games on the Hard difficulty setting with limited continues to unlock the Desktops 2 and Special Music.

Easy Tokens
Play Metal Slug 3 or Metal Slug 5 on the Hard difficulty setting. Immediately after you defeat the final Boss (when the Boss is going up in flames), save the game, then quit to the main menu once the credits begin. You should get five Tokens. Then, load the saved game file and repeat as many times as desired.

Special Music
Successfully complete Metal Slug 1, 2, 3, 4, 5, and X on the Hard difficulty setting with limited continues, and Metal Slug 6 with limited continues to unlock the Special Music.

Tonko art
Successfully complete Metal Slug 1, 2, 3, 4, 5, 6, and X on any difficulty setting with limited continues to unlock the Tonko art.