Cro-Mag Rally is one of the first 3D racing games on the iPhone. Unfortunately, as a racing game on its own, it stands pretty poorly. Let's sort out the basics: this is a straight up port of the same game released for Macs around 10 years ago. It shares the same interface, graphics, models, levels, and sounds as the original.
Once you get into the game, however, you'll see how little effort Pangea actually put into the port.
The first thing you'll discover is that all levels and vehicles are unlocked from the start. There's no campaign or time trials mode. Neither placings or times can be tracked; in fact there's no timing mechanism at all. Even if you wanted to keep track of your best times in your head, you're out of luck. There's extremely little incentive to play this game, and why Pangea could not be bothered to implement any of these standard features is simply mind boggling.
You'll always face 3 other racers (computers) in Cro-Mag Rally. There are some offensive items to help you out here, but aiming these with any sort of success is nearly impossible. Should another racer ram into you, you'll go spinning out of control and will probably have to turn around. This happens often and is not very fun.
Levels are way too long, and often boring. There are few (if any) real shortcuts, one dimensional obstacles, and bounding walls. Some tracks are way too narrow to be fun while others are too wide. On the plus side you get differently themed powerups depending on the level, but you'll quickly find that they're all very similar in nature anyway. Collision is atrocious and you'll go flying all over the place should you run into a wall at a high speed.
The controls are what you'd expect: turn the iPhone left or right to steer. Acceleration is handled by pressing on screen. The display rotates when you turn (the idea being to keep the view horizon straight), but this is ultimately disorienting and you'll be swerving violently from side to side in order to try and compensate.
Framerate is a huge issue in Cro-Mag Rally, and the iPhone is not necessarily to blame here. While other 3D iPhone games like Super Monkey Ball run extremely smoothly, Cro-Mag slows down frequently depending on what's happening on screen. Some levels are worse than others, but the game seems to crawl along in general - never offering a truly smooth experience.
The Settings screen offers a glowing parallel of the overall effort: a mess of iPhone style controls on a blank white screen that does not match either the standard iPhone interface or game interface styles. Clearly thrown together in the least amount of time possible.
I bought Cro-Mag Rally for the $2 price, and even now am feeling a bit of buyer's remorse. It's an OK time waster, but overall a rushed effort that I'll probably never play again. Don't be fooled, there are much better games you can buy on the App Store, even at $2.