Developers have yet to show off what iOS 8's Metal technology can do for games, but the new Unreal engine has gotten a very impressive little tech demo. Zen Garden lets you wander around a house built on a rock floating in space. As a graphics demo, it's very impressive, but that comes at a price: I couldn't even get this app to open on my first-generation iPad Mini.

Though a technically impressive demo would be little more than eye candy, this app actually allows for a little bit of interaction with a Zen garden you can rake with your fingertips, hence the name of the app. It's likely meant to show off particle rendering in the engine, but it's actually a neat little time waster.

What's Good: Fun little time waster, shows off the power of your iOS device.

What Sucks: Crashy on some devices.

Buy it?: If you're curious about what iOS can do graphically. Grab Epic Zen for free on the App Store.