I don't see why you are getting downvoted. In any case, the hand and the form of the shadow people is pretty much the only blatant giveaway. Its getting near impossible though, especially if someone simply modifies the giveaways away.

Look closely at the mic. Why does the grille look so organic and asymmetrical?

Look at that skyscraper. What in the hell is that blue thing on top of it?

You just have to look for like 3 seconds to see that this is slop.