shattered horizon

Probably the first dx10 only game. Halo 2 doesn't count because it was only artificially locked to vista and can be hacked to run on XP. Wiki entry here.

Very interesting concept. It might give you vertigo though. And plus points to people who are reminded of Ender's game.

System requirements are pretty high

Minimum Requirements:
Shattered Horizon requires DirectX 10 on Windows Vista or Windows 7.
There is no support for Windows XP or DirectX 9.

CPU: Intel Core 2 Duo E6600 / AMD Athlon64 X2 5600+
GPU: NVIDIA GeForce 8800GT / ATI Radeon HD 3870
GPU memory: 256MB
Hard disk space: 1.5 GB
RAM: 2GB
Sound: Windows Vista compatible sound card

Recommended Requirements:
Shattered Horizon requires DirectX 10 on Windows Vista or Windows 7.
There is no support for Windows XP or DirectX 9.


CPU: Intel Core 2 Quad Q6600 / AMD Phenom II X4 940
GPU: NVIDIA GeForce GTX 260 / ATI Radeon HD 4870
GPU memory: 512MB
Hard disk space: 1.5GB
RAM: 2GB
Sound: Windows Vista compatible sound card

source
in reference to: No gravity, one gun, no problem: Shattered Horizon interview (view on Google Sidewiki)