This would be interesting to try.

From the press release:

    TopWare and in-house developer Reality Pump have truly stepped up to the next level in fun for the iPad 2. This unique version of Two Worlds II: Castle Defense institutes 3D-ET™ technology in gaming for the first time ever. Making huge modifications to the strategy game’s engine for the mobile iOS platform, the Eyetracking system allows the player to “look around corners” in a strict sense of words. All without the annoyance of any extra needed equipment like special glasses. The camera inside the iPad 2 recognizes the position of the viewer and changes the perspective of the game regarding the player’s point of view.

    To allow everyone to experience this impressive new technology, 3D-ET™ is free even on the Lite version of Castle Defense, which can be upgraded with single level purchases. Of course, the offer is also available to owners of the full version.

    TopWare Interactive CEO, Dirk P. Hassinger explains, “by introducing the new Eyetracking technology we are ahead of the competition once more and will expand this edge in the future. Right now we are adapting the system for more platforms like PC or Mac and will also present some challenging 3D surprises within the next couple of months.”