This is the font that appears throughout most of the game such as in the HUD, menu and more. It also appears in the sequel Ratchet and Clank: Going Commando.

Here's some game-play videos of the two games with the font displayed many times:
http://www.youtube.com/watch?v=ULAEIMsm_CA
http://www.youtube.com/watch?v=_-SRY2EM-N4

Simian Display  Suggested by Dan 15