Here is information about the Tessellation Package for Crysis 2. (Direct X 11 and high resolution textures.)

DirectX 11 Ultra Upgrade

The DX11 Ultra Upgrade is a free visual improvement add-on introducing DirectX 11 support as well as a wealth of graphical improvements and perfomance optimization for both DX11 and DX9 API's.

When using the new "Ultra" spec DX9 platforms will beneficiate from the realtime local reflections and contacts shadows. The owners of DX11 platforms, in addition, will be able to enjoy hardware tessellation (requires the installation of the “Tessellation Package”), parallax occlusion mapping and several improvements for shadows, water, particles, depth of field and motion blur.

Crytek had also put up descriptions for both the Tessellation Pack and the High Res Textures pack, both of which are free to download.

DX11 Tessellation Pack

This free package containing pre-tessellated geometries is neccessary in order to be able to enjoy hardware tessellation on DirectX 11 graphcis cards. A compatible DX11 graphics card is required.

High Res Textures

This high resolution textures package provides higher textures resolution for a wide variety of assets. It supports both the DX11 and DX9 versions of Crysis 2. A 64 bits operating system and graphics card with at least 1 GB memory are required.