biggest surprise for me, even more than the ending, was the return of the Red Skull! Especially as vocal as Hugo has been about not wanting to be in another Marvel film. About that ending; in the trailer, the end was foreshadowed "You will learn to lose". Expected a major character to die, but not more than a dozen! Like
@Night Prowler said, have no idea how this gets resolved next year. Wonder if we will see Stark telling Aunt May that Peter is dead? During the trailers when i saw Nomad, i knew he was wearing a dark suit, but it was not until i saw the film that i noticed it is his Captain America uniform (he just hasn't washed it in 2 years!). Never heard anyone refer to him as Nomad. Quill sure screwed everyone; they almost had Thanos. I did not enjoy Banner not changing to Hulk. He was missed.
Really loved the after credits scene with Fury calling Captain Marvel.