Cars 2 AppMATes is a free iPad app that can be played entirely on its own, letting you drive a virtual, talking car through the familiar world of Radiator Springs from the Disney/Pixar film series, but it's the specially configured plastic cars that make this app unlike anything else out there. Well, when they work properly.

The Mobile Application Toys (the "MAT" in the title) come in two-packs sold for about $20 a pop, and let you command small versions of Lightning McQueen, Tow Mater, and other colorful vehicles seen on the big screen. While the cars themselves resemble Happy Meal toys, it's the little sensors on the bottom that let you place and drive them around the iPad screen, taking part in missions and brief collection quests as the world scrolls around your car.

It's an exciting effect when it works, but it's not a common enough occurrence to actually recommend shelling out for these tiny toys. At times, the cars performed admirably on the iPad screen, letting me zip around the open city and interact with other vehicles like I was controlling a digital avatar, which you can do if you choose not to buy the cars (Lightning is free, with other cars sold within the app).

Other times, though, the physical cars wouldn't register at all, or would lose the connection in the middle of a race, leaving me stranded without explanation. And the younger target audience isn't likely to respond as rationally to such failures. The app itself is solidly enjoyed without the cars, but it's a pretty sleepy affair without the tactile thrill of manning a toy vehicle.

The bottom line. Cars 2 AppMATes is sadly best experienced without the toys it's designed around – which was pretty much the only great reason to spend much time with it.