Just in case the economy of video games wasn't in enough flux for you, along comes the newest and strangest chapter in the long-running "MX vs. ATV" series.

You didn't think that the $40 retail price -- down from the usual $60 -- was because THQ loves you, did you? Rather, it's the basis of a new pricing plan that, if successful, might become a new normal.

"Alive" arrives with the best iteration yet of its unique brand of off-road racing. It also comes standard with a smattering of tracks and single- and multiplayer (two players split-screen, 12 online) modes. Initially, most of the tracks and events are locked, although every mode has a few that are available to play straight away.

A single experience points bar accrues experience across every mode of play. Upgrade the level, and new parts avail themselves to your rider and his motorbikes and ATVs. Achieve certain milestones, and you get faster vehicles, new tracks on which to ride them, and new events (online and offline).

Beyond that? Open up your wallet.

"Alive" prominently features an online store in its main menu, and THQ plans to gradually stock it with events, vehicles and tracks you can purchase piecemeal, turning your $40 investment into whatever price you're willing to pay.

If you never drop another dime, there's still a respectable amount of content to unlock simply by playing the game and leveling up. (New copies of the game include a voucher for a free download that includes what are, until you reach Level 10, the best tracks and events in the core game.)

But for being a game that's all about the art of the continuous reward, "Alive" unlocks that core content at an aggravatingly slow pace. Until you reach that 10th level, you're stuck riding the same four long tracks, two short tracks and three free ride environments (voucher content included) ad nauseam. As new events becomes available, you repeat the process until you hit Level 25.

The idea, of course, is for you to alleviate the tedium by buying new stuff online. But this so-called flexibility comes at the expense of the more full-featured career modes from previous games.

But if you have to ride these tracks over and over, at least it's fun to do so. "Alive" continues the heavy infusion of physics that really came into focus in the previous game, asking players to control their rider's body and position while simultaneously controlling the vehicle.

The dueling weight factors (along with the effects of heavy track deformation) add a subtle but unmistakable layer of strategy to the art of cornering and fighting for position. But none of these factors works at the expense of the speed, danger and general freneticism that has made the games so accessible all of these years.