What characters and skins can I unlock?

Solution 1:

There are a total of 8 characters. 2 are unlocked immediately (CommanderVideo and CommandGirlVideo). Five of the other characters are unlocked one per world. The last one is unlocked by completing all 25 Retro Challenges.

Commander Video (9 skins) - Default

• Default: (1) (2)
• Beat.Trip: (1) (2)
• Gettin' Schlortzed: (1)
• In the Buff: (1) Unlocked in World 2, Galloping Gangplanks
• Power Mitten: (1) Unlocked in World 2, Crate Expectations
• Inversion: (1) Unlocked in World 3, Morning Wood
• Mac Daddy: (1) Unlocked in World 3, UFO OMG
• For Android: (1) Unlocked in World 4, Devil's Marbles
• F...ing Turkey Suit: (1) Unlocked in World 5, Afterglow

Commandgirl Video (8 skins) - Default

• Default: (1)
• Purple Swan: (1)
• Throw Back: (1)
• Rebel Belle: (1) Unlocked in World 2, Soggy Bottoms
• Packed: (1) Unlocked in World 2, Listing Isthmus
• Jog Now: (1) Unlocked in World 3, Bigfoot's Big Foot
• Inversion: (1)Unlocked in World 4, Pilce Bump
• Riveting Laborer: (1) Unlocked in World 5, Supraliminal Slide

Unkle Dill (6 skins) - Unlocked in World 1 (The Welkin Wonderland), Every Cloud

• Default: (1)
• Gag on This: (1)
• Cucumber Bumpkin: (1)
• Clever Pickle: (1) Unlocked in World 2, Salty Sprint
• Made Man: (1) Unlocked in World 4, Bumpin' Ulcers
• Tough Gerkin: (1) Unlocked in World 5, Response-ability

Reverse Merman (6 skins) - Unlocked in World 2 (The Emerald Brine), Salty Splendor

• Default: (1)
• Bowled Over: (1)
• Playing Koi: (1) - Unlocked in World 2, Fluid Freeway
• Mecha Mahi: (1) - Unlocked in World 3, Blabbage
• Highly Trouted: (1) Unlocked in World 4, Grumbling Cravages
• Re Fezzed: (1) Unlocked in World 5, Extralogic

Whetfahrt Cheeseborger (6 skins) - Unlocked in World 3 (The Supernature), Slap Stick

• Default: (1)
• Pretty: (1)
• You Höser: (1) Unlocked in World 3, Lumber Jackson
• Get Blue: (1) Unlocked in World 2, Aquatic Symphonic
• Kung Fu Fighting: (1) Unlocked in World 4, Sweaty Dangle
• Vegetarian: (1) Unlocked in World 5, Hyperbrain

Pitazo (6 skins) - Unlocked in World 4 (The Mounting Sands), Grumble Gallop

• Default: (1)
• Heart Transplant: (1) Unlocked in World 2, Brine Time
• Zap a Toes: (1) Unlocked in World 3, Harsh Gribaldeen
• All Brassed Up: (1) Unlocked in World 3, Treeathalon
• Boarding Call: (1)
• Can't Catch Me: (1) Unlocked in World 5, Hypnogogic Logic

Captain Video (6 skins) - Unlocked in World 5 (Bit.Trip), Sweet Eyefuls

• Default: (1)
• Long Run: (1)
• Super Saver: (1) Unlocked in World 4, Wrongledoo
• Done Up: (1) Unlocked in World 4, The Doleful Unders
• Manly Runner: (1) Unlocked in World 5, Megathon
• Hardcore: (1) Unlocked in World 5, Ultravision

Retro CommanderVideo (1 skin) - Unlocked by completing all 25 Retro Challenges

• Default: