Ratchet and Clank has been one of my favorite games since the ps2. I have played through all of them (except Quest for Booty as well as Secret Agent Clank), and I have to say one of the greatest series of all time. Then again you have to enjoy third-person shooters, and even *gasp* jokes.
Storyline: This one takes off immediately from Quest for Booty,or so I've been told, and don't worry you don't have to play Quest for Booty to understand this. Though I would recommend playing Tools of Destruction to understand the backstory, as well as Up Your Arsenal on the PS2 <---- though not needed on this one. The game takes place in the future, and you play as an bipedal anthropomorphic cat, or Ratchet the Lombax. He has been thought to be one of the last of his kind. Turns out he is not. You also get to play as Clank, a robot, who in the earlier games was just a backpack with a few cool things he could do for you, such as hover across longer distances. But in this one he has the power to reverse time, and cool stuff like that. The Story in this game is pretty good for the Ratchet and Clank Series.
Gameplay: Since you no longer have Clank as a backpack, it is a much different gameplay, or it was to me anyways. This game does have a lot of the same gameplay to it though, even though Clank is gone. Yes there are new worlds and new puzzles, but a lot of things returned, such as the grindrails. Don't get me wrong, I love a good grindrail (wow that sounded a little wrong), but having to do it a million times (over-exaggerating) gets a little annoying. They did have hoverboots, which are boots that make you go faster. There were new gadgets and a lot of other things that added a lot of good gameplay. One other thing is that Clank's gameplay was probably one of the funnest parts of the game, as well as one of the most frustrating parts. Clank's gameplay was basically figuring out puzzles, much like the flash game chronotron ( which I recommend playing).
Graphics: Pretty good for a PS3 game, much better than Tools of Destruction. The art-style stayed much like every other game in the series. Really not much to put here except that the Graphics looked good and reminded me of other games in the series. I don't know much to say except Insomniac knows how to push their games.
Overall: Great game that has great new gameplay to it. Loved how they brought back some of the old stuff, as well as new stuff. A must buy for any Ratchet and Clank fan.