Ratchet: Deadlocked Hints & Cheats

Go to the pause menu and press the following buttons on the D-pad to unlock the corresponding skin. This only works in the Japanese version.

These are given to you in Challenge Mode after completing various goals:

Ratchet will be faster, in my opinion better looking, in other words better.

Beat the game once and start Challenge Mode to unlock these features in the Media menu:

At level 99, weapons get a rainbow color effect added to their shots.

Finish the game once in normal mode (in any of the first four difficulties) to unlock the 5-star Exterminator difficulty (and challenge mode). Now you can either select the Exterminator difficulty when you play your game again in challenge mode or you can start a new game from scratch in the Exterminator difficulty.

To get the epilouge you have to beat the game and watch the whole entire credits.

After gaining access to the Battledome Challenge "Endzone", use the Holoshield Launcher and/or Mini-Turret Launcher with Shock Mod equipped. After setting up the shields and turrets, equip whatever weapon you want to upgrade, making sure you have the Shock mod equipped. Complete the challenge and repeat until you upgrade your weapons to the desired level. After being able to buy Experience/Jackpot Mods, max out the alphamods on the weapon of your choice to rapidly get to lvl 99 weapons and/or make millions of Bolts.

Go to any Boss Battle and play it. When you start, the game will automatically reload all of your weapon's ammo. Exit the challenge and your ammo on all of your weapons will be reloaded for free. This way you do not have to spend your bolts on ammo.