I know this is an old video but it was shown as a gameplay movie. On PC with every graphic option max, I don't get this much quality graphics. The shadow, lightning and the motion, it plays is amazing.
Also It seems like there are better cutscenes. Towards the ends in Part 3 you see your squad discover green (weapon?) stuff and it looks far more interesting then the cutscenes in final game. Also animations seems smoother.
I feel like a lot of stuff from game is cut but where did hey go? Why would you make amazing game and make poor decisions?
