I´m compiling a list of Crysis DX9 vs DX10 features, here´s what I came up with so far:
DX10: Weapons - sniper rifles, rocket launchers, pistols, grenades and more.
DX9: You can press ctrl to punch. However, there are no animation.
DX10: Open-ended gameplay with more than one way to accomplish missions
DX9: There´s a room to the left of the end boss with ammo and health.
DX10: Physics System supporting vehicles, rigid bodies, liquid, rag doll, cloth and soft body effects.
DX9: If you walk through a tree, the game crashes.
DX10: Animation System: Playback and blending between motion data (captured or key framed) combined with inverse kinematics (using biomechanical hints) and physical simulations.
DX9: When you shoot someone, there´s some smoke and then he instantly disappears.
DX10: Data-driven Sound System: Complex sounds can be easily created and offer innovative use.
DX9: When you walk over a health crate, the Windows Startup wav file plays.
DX10: AI System: Team based AI and AI behaviors defined by scripts.
DX9: When an enemy runs out of ammo, there´s some smoke and then suddenly he disappears.
DX10: Shaders: A script system used to produce visual effects. Supports real time per-pixel lighting, bumpy reflections, refractions, volumetric glow effects, animated textures, transparent computer displays, windows, bullet holes, and shinny surfaces.
DX9: All mirrors will show an image of your character. It never moves, tho.