For one thing...a TECH DEMO IS A DEMONSTRATION OF HARDWARE, in this case, that was demonstrating the XBOX 360, note that it was release around 360's release, it is not a promo video nor an early build.

You can also say what happened with the FFVII PS3 Tech Demo that was also released around the PS3's release which we all know won't be made unless they get the people for it and I can guarantee it will be scaled back.

FFXIII, FFXIII-2 and FF Versus XIII are CT games, "clipping" is found in every engine.