In an open letter to the community Crytek's Cevat Yerli announces the delay of the Crysis single-player demo until Oct 26th. But he promises goodies for the wait...
While we won't see the demo now until Oct 26th, 2007 - fans will be rewarded for the wait with the CyEngine 2 - Sandbox 2 game editor so those amongst you who shall be crowned king of all map makers by the Crysis community can get your learn on! 
Here follows the WORD as it cameth from on upeth high:
Hi everyone,
We have some news to announce. First, I am sorry for the bad news - the Crysis single player demo will now be available everywhere on October 26th, 2007.
We are taking some extra time to make sure you that you have an amazing experience but also we did not want to risk the release date of Crysis at this stage. To get the game into your hands by November the 16th, we had to make this call.
Now the good news - the big surprise. The SP demo will be released with our CryEngine 2 - Sandbox 2 game editor, giving the community the opportunity to get familiar with the vast amount of tools they will have at their disposal four weeks before we ship, something we have always wanted to do.
This is an exciting time for us at the studio as the development of Crysis comes to an end and we are only a few weeks from Gold Master. We appreciate your patience and are looking forward to getting Crysis into your hands on November 16th.
Thanks
Cevat Yerli
CEO & Crytek I see this as a very positive move. For one the demo was scheduled to land day and date with the release of
Halo 3 - and if today's frenzy by the press over the builds many of us received early is any indication -
Crysis would get lost in that noise.
Not to mention the heavy work the team has to do to ensure the demo stands by itself - and this pulls valuable cycles away from the finished product - which personally - is much more important to me than the demo.
We'll have our multiplayer beta impressions next week.
Now, back to
Halo 3
demo for crysis it`s available 4 download http://www.pixelrage.org/downloads/Crysis-Single-Player-Demo/3048.html