MX vs. ATV Unleashed arrived in early 2005 for consoles and early this year for the PC and turned out to be an engaging mix of off-road arcade racing, featuring the requisite MX bikes and four-wheel ATVs. While those two vehicle types were the centerpiece, they were far from the only option available--the game also let you race monster trucks, dune buggies, golf carts, and even helicopters and airplanes, to varying degrees of success. With MX vs. ATV Unleashed: On the Edge, the series now arrives on the PlayStation Portable, and while the fast-paced racing experience hasn't changed that much from the console games, there are some key differences that fans of the series need to know about before rushing out to the store to pick this one up.

ATVs, MX bikes, and plenty of other off-road racers are at your fingertips with On the Edge.

At its heart, On the Edge is a dirt racer, with MX bikes and ATV quad-racers tearing around supercross tracks and outdoor courses, full of massive jumps, hairpin corners, and stiff competition from up to three on-track opponents. One of the best parts about On the Edge is the tracks themselves, especially the outdoor nationals courses, which pack plenty of imagination and challenge in their relatively short length. Leaping massive gulches, perfectly tackling a chain of medium-sized jumps, or ripping up the side of a cliff, only to hang a U-turn and head back directly down that same sheer slope can be a real thrill. Unleashed veterans will recognize many of the courses found in On the Edge--from the muddy, mountainous test of Tipperary to the breezy and fast-paced Oceanside course, these outdoor courses are a lot of fun to drive. The stadium supercross tracks don't fare as well--most are too similar to stand out from one another--but when you add them to the short tracks, waypoint races, and open-class events, it all adds up to a roster of single-player courses that will keep you busy for a while.

Then there are the vehicles--MX bikes, available in four flavors (from 50 cc all the way up to 500 cc), and ATV racers, which are more stable on jumps than the bikes but a bit underpowered by contrast. All of the other crazy vehicle classes can be found in the game, but it takes some work to get to them. The only way to get to the open-class events is by unlocking the series using store points, which you earn by performing tricks while in races or in freestyle events. While it seems like the developer wanted to put the focus squarely on the MX and ATV portion of MX vs. ATV for the PSP, making it difficult to reach the other vehicles that appear in the game--such as buggies, golf carts, trophy trucks, and sand rails--seems like an odd choice, especially since it was partially that "kitchen sink" mentality that kept the console version of Unleashed feeling fresh.

From a control standpoint, the game feels very similar to its console cousins. You accelerate using the X button, brake with the square button, steer with either the analog stick or directional pad, and pull off a variety of points-earning stunts using the triangle or circle buttons (with the right triggers as a modifier). One of the biggest differences between the console versions of Unleashed and On the Edge, however, is the sensitivity of steering. It takes some practice to get used to the twitchy steering of the analog stick, especially on tight corners; it's all too easy to completely turn your rider around or accidentally head off the track during particularly hairy sections.

Tackling jumps correctly is the essential ingredient for speed in the game.

Tackling jumps is the most important skill you'll need to develop in On the Edge. Mounds of dirt are strategically placed all over the tracks found in On the Edge--usually one after the other--and the easiest way to turn a quick lap is by finding the optimal method for taking on these chains of jumps successfully. One of most effective methods you'll have for handling jumps is the ability to preload your suspension. Before heading off the lip of a jump, you pull back on the analog stick, and as you cross the lip, push forward, thus giving you an extra bit of momentum as you head into the air. Pull it off correctly, and you can gain a lot more air than you would in a normal jump (and even toss in a stunt if you're so inclined). You'll still need to nail your landing, however; if you hit the apex of another mound or land at a strange angle, you're sure to send your rider into the dirt. In the end, On the Edge's challenge is determining when to use these preloaded jumps and when not to--they aren't useful in every situation. Often, especially on the more complex courses, this is a matter of trial and error, which can lead to some frustration, depending on your tolerance for this type of thing.