If you've played any of the Backbreaker games--particularly --then you'll feel right at home in NFL Rivals. As in those other NaturalMotion games, you control a running back trying to sprint down the field and into the endzone without getting tackled. Tilting your iPhone or iPod touch changes your running back's speed and direction, while onscreen controls help you deke, spin, jump and bulldoze your way through defenders. In a Defense mode, you're the hunter, not the hunted, with the on-screen controls helping you avoid enemy blockers. All the praise I've had for previous versions of Backbreaker Football applies to NFL Rivals: I really appreciate how the game puts you right in the action. My criticisms stand, too: I wish the jump control were more clearly defined so that I don't tap another on-screen control by mistake.

A glance at the App Store page for NFL Rivals reveals some users have reported problems with crashing. I never had a hint of an issue during my tests. It's worth noting that the graphics for this game, as with many of NaturalMotion's iOS offerings, are pretty demanding--you'll need at least an iPhone 3GS or third-generation iPod touch to play the game. (And as I said, NFL Rivals ran smoothly on my iPhone 3GS.) Earlier models of either the iPhone and iPod touch just don't have the processing oomph, which may explain some of the negative App Store reviews.

Is the NFL tie-in enough of a differentiator from the other Backbreaker Football games? That depends on how much you want to don the colors and logo of your favorite team. Die-hard fans will probably love to see the Colts' horseshoe, the Saints' fleur de lis, or the Raiders' eye-patch-wearing reprobate on the helmet of a video-game character they control. For me, the official uniforms and global rankings of NFL teams didn't add much to the experience; in fact, I rather prefer the virtual teams of the other Backbreaker-style games. But for iOS game-loving NFL fans, NFL Rivals is another way to let you true colors show.