Neven Mrgan, a developer at Panic, as well as the co-creator of the popular Birdfeed Twitter client, has just released a fascinating new iPhone game. It's called Pie Guy, and the gameplay is reminiscent of classic Pac Mac games.

You won't find Pie Guy in the App Store, though, because it's a web app. You can even add it to your home screen and play it offline. The game is fairly fun, but the more exciting part is what it suggests about the future of web apps on the iPhone.

All those problems with the App Store approval process don't apply to web apps, so it's worth seeing how far developers can push web apps. They're not an alternative to every iPhone app, as John Gruber points out at Daring Fireball, because web apps don't have access to a lot of the iPhone's hardware functions (accelerometer, camera, etc.).

On top of that, the Cocoa Touch framework makes native apps not only faster than web apps, but easier to write. Despite all that, Pie Guy makes a good case for expanding our ideas of what a web app can be.