After killing Barnes, Taylor's about to commit suicide with a gernade right before he's discovered by the U.S. troops.

So, this isn't something I "just noticed" as much as I "finally understood" upon my most recent viewing.
Near the end, when Pinbacker is stalking around, killing everyone, I didn't get why Danny Boyle used such weird cuts/angles/distortions/etc.
I figured he was just getting overly stylistic as the film changed frim Sci-Fi Drama to full-on Survival Horror.

But I realized that it all goes back to a comment made by Capa (Cillian Murphy's character), that, as the ship gets closer to the sun, time becomes irrelevant/distorted/whatever (I'm paraphrasing here). So, Boyle's change of style for the third act actually makes sense. It may not be the best representation of what he was trying to accomplish, but with that mindset as a viewer, that's how I interpret those scenes. It's not flawless, but it works for me and has increased my enjoyment of the film (especially the final act, which a lot of people seem to hate).

When Doc and Marty go to the train station to look at the map, you can see teacher standing in the background waiting to be picked up and also at the beginning you can see the mall called Twin Pines Mall but when Marty returns (after destroying one of the two trees after going back in time) the mall is called Lone Pine Mall.