Skill Points: collect these points and unlock the cheat option needed:
Big Headed Giant Clank: 1
Big Headed Clank: 3
Big Headed Ratchet: 5
More Cowbell: 8
Mirrored Levels: 10
Super Bloom: 12
Big Headed Enemies: 14
Weapon Switching: 16
Bolt Confusion: 20
Hardcore Mode: 24
Mooo!: 24
Old Timey: 24
Climb The Treehouse: 25
Titanium Bolts: collect them to unlock the corresponding skin under the “Specials” option in the pause menu:
Troical Vacation skin: 4
Plundering Pirate Captain skin: 6
Ratchetzilla skin: 6