The Adrenaline Vault Downloads Demo has a 31 MB playable demo from NovaLogic's upcoming Delta Force 2, the sequel to their voxelated first-person shooter that emphasizes tactics. Here's the word on what this release can, and can't handle, as far as video:

The pre-release version of Delta Force 2, supports a limited number of 3D cards. Delta Force 2 will support cards that are truly 32 bit color polygon renderers, including TNT, TNT2 and ATI Rage Fury. 3D card support is provided through Direct 3D. DirectX 6 or greater is required. Note that only polygon-based objects in the game will be accelerated.