Hanna was a solid film with some great action bits and acting, so that's a plus for this.
I just think SotC is so distinctly video game that they will either make a poor film or have to adjust so much that much of the game will be lost.
If they follow three act structure be three Colossi. First one to introduce, second to be test and third one to bring closure. This could be done in about two hours, but pacing will be key in setting the mood and giving weight to the characters actions.
I would say I expect the worst and hope for the best.