I've seen many videos that show case features that were left out of the full game.
http://www.youtube.com/watch?v=a2UCnblmOMY
Go to 1:50, there is actual procedural destruction of the tiles, rather than small bits of destruction in the final game.
At 1:17 the small trees can be cut down until in the full game.
http://www.youtube.com/watch?v=U4wdYftp1rA
In this PS3 video at 1.23 you can see big trees being cut down, just like the palm trees in Crysis 1. In the full game, big trees are completely static yet in this hacked version the feature is there.

I've also seen things like tesselated ocean rendering that is also left out of the game. In this screenshot the caption says "Extreme Spec" even though in the full game you still have crappy console water.
Seems like we have a big DX11 patch upcoming if Crytek are serious with their, "making full use of DX11" comment. And even if they aren't we'll still get this since these are plain DX9 features.
I hope we will get these features shown in this videos...