Like most puzzle games, the basic gist of Gunpey is easy enough to grasp. Tiles rise up from the bottom of the screen on a timer or at your behest, each stamped with a straight or bent line, and you must vertically swap them to create lines that connect the left and right sides of a 5x10 grid. Lines may fork and zigzag, depending on how you arrange the pieces, but only paths that reach all the way from left to right will disappear.
At first, it seems like play consists of little more than a rush to swap pieces to stranded top-most tiles in an effort to make them disappear before they reach the top of the screen and end the game, but you'll quickly find that skill progression proceeds at an almost subconscious level. You seem to get better the more you play, even if you don't actively seek out the patterns and strategic moves that unlock the true pleasures of Gunpey. Once you commit to the experience, however, you'll find it wraps itself around the primitive, obsessive core of your brain and won't let go. Just... one... more... line. Sure, buddy. You can quit anytime you want.
What keeps Gunpey from being a true new puzzle classic, despite all the Lumines -esque trappings of unlockable skins, varying music, and line-breaking effects, is that the core experience doesn't lend itself to much variety. There are "original" and "break" rule sets that determine whether tiles above a destroyed line fall or not, but that's the only substantive variation on tap. In fact, the only real gameplay difference between one skin and another is the rate at which the tide of tiles rises.
No frills time trials come in 60, 90, and 180 second flavors. The standard challenge mode unlocks skins as you progress, which can then be used in a standard single skin mode, and a double skin mode that challenges you to contend with two boards of tiles at once. There's also an oversized 10x10 board that'll give your left thumb one hell of a work out. Trouble is, there's nothing here to vary the convoluted strategies you'll discover, even when playing a friend over an Ad Hoc Wi-Fi connection.
The PSP, with its bizarre animations and pulsing music, offers a sharper and much more satisfying overall presentation than the Nintendo DS version, but it lacks the goofy characters and CPU opponents, not to mention the handy ability to drag and swap tiles with the stylus.
Disappointment about the lack of groundbreaking invention aside, Gunpey is a fun and intellectually interesting workout for brain and thumbs alike. If you're sick of falling blocks, or just need some new challenge to wrap the grey matter around, give it a go.