The technical aspects of Chinatown Wars were impressive on the DS, and the PSP version looks quite a bit sharper and cleaner than the original release. It maintains the same top-down perspective that fueled the original Grand Theft Auto games, which may seem a bit weird to PSP owners, since Sony's handheld has received GTA games that look a lot more like their console counterparts. Chinatown Wars is better than those games, both because it has a cool, stylized look and because it simply plays better this way on a handheld.
The PSP version of the game also makes some interesting additions and changes that help adapt this DS game to a system that only has one screen that doesn't do anything, no matter how hard you stab it with a stylus. Without a second screen to fill with information, the game's minimap is a bit hard to deal with. So the smartest thing you can do is go into the options and turn on "World GPS," which draws route lines on the actual road. Unfortunately, you'll still have to go into the pause menus and look at the map to plot destinations when you're not on a mission. Loading up the menus takes a little bit of time, and navigating the map to drop waypoints isn't all that slick with the PSP's controls.
However, putting up with menu navigation is pretty minor in the grand scheme of things. GTA: Chinatown Wars is a quality product that gives you a camera perspective and gameplay that fits really well on a handheld. It might not be quite as ambitious as attempting to completely duplicate the console experience (like the "Stories" set of PSP releases did), but it works wonderfully and catches plenty of the GTA experience, despite the different perspective and still-frame cutscene style. If you're looking for this sort of open-world game on your PSP, approach without caution.
For more details on the story and other gameplay elements of Grand Theft Auto: Chinatown Wars, be sure to check out our original review of the DS version, which covers these elements in more depth.