Sony has released a free-to-play endless runner set in the R&C universe - Ratchet & Clank : Before The Nexus
, a prequel to Into The Nexus. The game is fun and it makes good use of the R&C elements, but the control isn't as tight as it should be. The free-to-play stuff isn't bad, thankfully, and it shouldn't be too hard to earn everything just through playing the game. You can also earn raritanium in the game that can be transferred to Into The Nexus on PS3.