One of the only problems we have with PQ2 is that it's definitely not conducive to on-the-go play sessions. Not only is each puzzle timed, but some of them are so brain-strainingly difficult that we had trouble completing them, even with 100% of our attention focused on the game. Forget about acing the trickier puzzles on a crowded bus or in a noisy classroom. Unless you're a super-genius, it's not going to happen unless you have zero distractions or resort to trial and error.
With over 250 new puzzles and a level editor to create your own puzzles to send to friends, PQ2 is an easy recommendation for fans of the first PQ or anyone looking for a puzzle challenge on the PSP. Just ignore the fact that IQ scores (or PQ scores, in this case) are totally meaningless on every level. (If you actually believe your PSP can tell you how smart you are, there's no hope for you anyway.)