Yup. Spoilers. This list won’t be comprehensive or in order, I’m just going by whatever pops up in my mind first. Please keep in mind that my Japanese comprehension isn’t the best, so I may get some things wrong.
The first scene is Eva Unit 5 exploding in the US. There’s lot of English that’s mostly well acted by actual English speakers. Yamadera Koichi had some English as Kaji, but I had no idea what he was saying. In this scene Mari fights with Eva Unit 5 against what I assume is an Angel. Unit 5 explodes.
Mari and Kaworu don’t really do much. Mari is like some secret agent for the US NERV branch it seems.
Asuka is the test pilot for Unit 3 this time around. She has a daring test plug suit that shows off her butt. Unit 3 turns into an Angel, as usual. Shinji destroys it, Asuka dies. But… she doesn’t? In the preview for the next movie she’s shown right at the end with an eye patch.
Rei has some personality in this! She smiles, and even tries to make food for Shinji. It’s moe!
The ending scene is taken from the episode where the Eva goes really berserk and starts eating things. However, instead of going berserk, it goes super saya-jin, saves Rei from the inside of the Angel (the Angel ate most of Rei’s Eva, by the way) and theres lots of pretty lights. Cut to credits.
After the credits, Kaworu descends from the moon in his Eva, throws a spear at Unit 1, impaling it, and says something that I forget.
The side characters are really shafted in this movie version. Toji and Kensuke don’t do much, really, and Hikari isn’t really present at all. You do get to see Toji’s sister, though!
That’s about all the important stuff. I’m sure there’s better lists out there by now.
edit: Oh, and they cut out out the shadow Angel. I guess it wouldn’t really work in the context of this film.