I know, lots of post about this already, but I have to say something.
Shadow of the Colossus is one of my all time favorite games. It stands the test of time well. In fact, I just beat it again today. It still, after 4 years, looks beautiful, and is an epic experience. And one of the things that make it so epic is the mystery. It doesn't give too much information on back story. The sequel (ICO, which came out first, for anyone who is unfamiliar with the series) is also very mysterious. That being said, here is what my major problem with the movie would be:
It might add new plot that doesn't match up...
Don't get me wrong. I am all for a movie with a similar basis of a game, but with a different plot. Just not for SotC. The Resident Evil movies were ok. The DMC anime was fine. Those are two adaptions that did well. But I just don't see a SotC movie ending well.
The original game was a cinematic masterpiece. As many have said, it was beautiful, and emotionally provoking. It was one of the two games I've ever played that invoked a deep emotion other than hatred, boredom, or happiness. With that to compare too, the movie just cannot live up. Sure, I'd like to see a CGI fight in HD between a Colossi and Wander, but it probably won't meet the expectations that are set by the gaming community.
It most likely will need new plot for the movie. And that can go either way. On one hand, it could be faithful to the game, mostly canon story, and make most of us happy. But the more obvious thing that will probably happen, is that the plot will be way off. Hardly canon. And ruin the game for some of us because of it. Remember folks, you can never un-see something, no matter how hard you try.
Now, some people may not care about it being canon-like, and that wouldn't normally bother me. Hell, a movie is pretty much guaranteed not to follow the canon of a game, for a games canon is too complex or simple. But this is Shadow of the Colossus, not just any other game. The plot, if too far off, will feel like a mockery of SotC, which too me, is art. And why mock art?
As I said, HD CGI colossi = amazing beyond words. And I will go to see the movie just to see that. But that can't be the only thing. Sure, everyone loves action flicks, but with the above plot complications added in, that will majorly cut down of fight scene times. So with the cut down fight scenes, how will they fit 16 colossi in? The short answer is that they probably won't. And if they do, it'll be at least part montage. Or, the third possibility is that they make a trilogy, or at least one sequel.
The movie could range in time from 1.5 to 3 hours. During that, if they gave each colossi 10 minutes, the movie would become incredibly repetitive for most. Thats 160 minutes for the fight scenes. If the max time would be about 180 minutes, that leaves 20 minutes for the emotionally touching story. I don't see that happening. So (to me) that definitely means one of the three above choices out of point 3, will be used.
Don't get me wrong. I'll watch the film. I'll most likely shell out the cash from my wallet to get popcorn too. Flaws or not, its SotC. And if the film does well, it may motivate the geniuses behind the games to work a little faster on the 3rd in the series. But one can only hope, and you cannot rush good work.