I thought the time travel quest in the middle was pretty weak and overlong. It felt like the avengers greatest hits. The first movie felt like it had a lot more stakes than this one.
I will say they ended it pretty epicly though. I guess I would've liked if they got there a little more cleverly.
The time travel quest had so many great moments - character moments and fan moments:
- Cap saying hail hydra to get away with the scepter
- Cap facing off against himself and cringing a bit at the "i could do this all day" line
- Loki opportunistically zipping out with the tesseract (making you think "well what the hell are they going to do now?")
- reframing the post-battle portion of Avengers 1 to show the corruption already present in shield
- the payoff of dr strange's timestone plan, as giving it away is what convinced the ancient one to give the time stone to banner
- the ancient one's time-omniscience showing itself as she knows Dr Strange will come in 5 years' time
- gamora and war machine's little bonding moment over both being part machine
- cap's in-the-flesh encounter with Peggy that plants the seed of coming back to her and staying there
- stark's last chance to spend time with his dad — especially touching after his discovery of his dad's message to him in iron man 2
- Hawkeye and black widow expressing their love for one another in a fight to determine who'll die for the good of the universe and finally erase all the red on their respective ledgers
- Thor having the opportunity to see - and be really seen and understood - by his mother before her death. It was an encounter that finally helps him overcome his depression at failing to kill Thanos and to accept himself for who he is.
And there's more stuff I'm forgetting, but for me this was a great part of the movie.