With Ratchet and Clank: Size Matters, High Impact Games has created a PSP-sized original adventure for the titular heroes that is a worthy successor to past Ratchet and Clank games. Though you can save only items and not physical progress through each level, the levels are short enough that you could probably play this game on the bus or waiting in line, but it's immersive enough that you may well want to spend long, thumb-aching stretches with it.

* Complements the existing Ratchet and Clank franchise.
* Bright, cartoony graphics.
* Works for both quick or in-depth game sessions.
* Reasonable learning curve.
* Substantial multiplayer.

Cons
* You have to play through more than once for all the extras.
* A bit on the short side.

Description
* ESRB rated E10+ -- published by Sony
* Graphics: Lots of bright color; well-designed, cartoony characters; a few jaggies from time to time but otherwise great.
* Sound: Fun but not intrusive tunes, with different music for different settings; amusing and appropriate sound effects.
* Gameplay: Mostly easy to get the hang of (I still suck at racing), with a reasonable learning curve; also, it's just fun.
* Multiplayer: 7 online games modes for up to 4 players, using either Ad Hoc or Infrastructure.
* Replay value: Relatively high, especially if you want to unlock everything; unlockable Challenge Mode ups the difficulty.
* Recommendation: Unless you already dislike the RnC series, play this game; it's a must-play if you're a RnC fan.

Guide Review - Ratchet and Clank: Size Matters
I can't help but compare this game to Daxter, also a PSP-original game in an existing franchise that returns to its platforming roots to deliver a tonne of fun in a perfectly portable game.

Like Daxter, R and C: Size Matters builds up short, playable-on-the-go levels into an adventure that seems bigger than the sum of its parts. Both games also include minigames accessible from points within the game (and in the case of Daxter, a different minigame completely outside the main game) that add to the challenge and replayability of the title.

Like But Unlike
Unlike Daxter, Size Matters includes both of the series' main characters. The "size matters" of the title-- which can be taken to mean either that size is important, or that the game concerns matters of size--involves a shrink ray allow one or both characters to become smaller to face the miniscule main baddies. At one point, Ratchet shrinks himself to battle the enemy inside Clank's head and to repair his robotic pal.

It's All About the Weapons
As any fan of the series knows, a Ratchet & Clank game is all about firepower. And acid power and suck power and the power of little robotic minions. Despite the handheld-appropriate scope of the game, Size Matters sill has more weapons that any furry orange big-eared creature should be able to carry. Add in weapon mods you can buy for outrageous prices on the black market, and armor you can win in the minigames, and you've got plenty of toys to play with. Just trying out all the different weapons add to the replay factor.