I had about an hour and a half on the demo there. And I'm a little underwhelmed from the whole experience. There are serious problems with response times, especially in regard to shooting, with first time shots being most problematic.
It does play similar to PES 2009 but, similar is not the same. The change in game speed and gameplay (opponent A.I.) is quite apparent, at least to me. It may be subtle but, it does make a difference. I still play PES 2009 quite regularly and I can dominate more often than not, and even when not, still come out with a victory. The fact that I cannot do that in the PES 2010 demo (faults aside, as PES 2009 has its own faults) highlights the changes.
It has a slower pace. Dribbling is different; not as easy. The A.I. don't fall for the same old tricks such as the fake shot, turning back on your run to cross with an in-swinger as the defender continues going the other way, the stop dead and instant dash towards the opposide direction which always left your marker for dead, etc.
Is it better than PES 2009? It's difficult to say. Some things appear to be improved while others seem to have taken a step backwards or stayed the same. I personally cannot tell if this code of the game (demo) has 360* movement implimented, or if I simply have not got to grips with it, yet. It is more apparent in the FIFA 10 demo, though. And I'm still undecided in regard to the new tactics, formations, and card system menu/features.
Is it better than the FIFA 10 demo? No. The gameplay is not as fluid nor as responsive. And the passing is not as crisp. It is also not as difficult, and therefore provides less of a challenge. Although it should be noted I have not played the FIFA 10 demo as much. But that is on the agenda for later, to further compare the two.
And whether this code is 50% complete, 65% complete, or 80% complete, etc, it is irrelevant. This is a discussion about the demo, not the final product. They choose to release this demo, whichever code it is, and it will be judged accordingly. The point of a demo is to impress potential buyers, to excite potential buyers, and most of all to entice those potential buyers to part with their hard earned cash. That would have one assume that a demo would be, at the least, a close iteration to that of the final product. If it is not, then that is the pinacle of stupidity, because it will be detrimental to sales.
There is little to really get excited about from the demo, and that is hugely disappointing.