#1 -- Lumines

Few launch titles have aged as well as Lumines--an addictive puzzle game eith a dynamic soundtrack that few players who picked up the game could ever forget. The gameplay maintains its frenetic but simple time-based block-matching at all times while the audio and visual style radically shift after clearing a certain amount of bricks. Each round had it's own style and every PSP owner deserves to play them all.

Full disclosure: AJ Glasser was a QA tester on Size Matters during the pre-Alpha stage.

#2 -- Ratchet & Clank: Size Matters

This is the first game from the Ratchet & Clank series that ever hit the PSP -- and it didn't just hit it, it rocked it if Metacritic scores are any indication. The game was mostly an adventure on the same scale as any of the console games, with several mini-games thrown in for good measure. The whole game came together nicely on its own, but because of the fully-voice dialogue and the attention to detail in the story, Size Matters felt like so much more than just a "PSP spin-off."