Quest for Booty is a solid addition to series' storyline, giving players more of the same solid gameplay.
For the most part, the game has sort of a hub level design. There's one main large area that you explore and battle in several time, with several smaller areas that you travel to over the course of the game. Ratchet has a new ability - he can now tether his wrench to certain objects and move them around the game world. Sadly, while this is a new mechanic it feels a little tacked on. The puzzles in which this is used are underwhelming at best, mostly consisting of simple one or two piece affairs that lack any real challenge or complexity. The only downside I experienced was near the end, the battles became more trial and error than anything else, and the swarms of enemies often became difficult to manage. Finally, Ratchet can no longer upgrade his weapons by buying additional parts for them - they can grow stronger, but like the base game this simply happens once each weapons hits an experience level which is raised by using it in combat.
Visually, the game is on par or above Tools of destruction - depending on where you are - which means that these are some of the best graphics a PlayStation 3 game has to offer at the moment. The main island that you'll explore is the real highlight here - with it's bright blue water and swaying grass (that moves when Ratchet walks through it, no less). The art style comes together really well with the technical presentation to really give the game that great, fluid look that Tools of Destruction really nailed.
In the audio department, there seems to be an issue with game tracking sounds to the different speakers in a surround setup - for instance, if someone is behind you and starts talk, their voice will play out of the rear speakers correctly, but if you quickly swing the camera around it takes a few seconds for the game to move the audio over to the front/center speakers. Other than that, the big issue of the Combuster still sounding much louder than anything else still exists. For the most part, the rest of the audio is extremely solid.
Overall, I'd say this was well wroth the $15 it costs. It offered about five hours of game play (which isn't bad) and it teasingly carried on the storyline from Tools of Destruction. It's easy to tell this was Sony's way of experimenting with episodic content, so I hope the gamble pays off and a lot of people are interested enough to purchase this. I for one am really looking forward to uncovering more of the mystery.