First off, I don't think it was nearly as good as the last Avengers. Many of the characters seemed moody and irrational. They were really trying to pound home the idea that the Avengers were dealing with internal strife. It came off as overly emotional, and lacking the fun vibe of the first. And they never really provided the same sense of danger and urgency of the first one. Or a sense of completion at the end of the film.

Elizabeth Olsen as Scarlet Witch might be the worst Marvel actress yet. Totally worthless. She had the same emotionless botox-frozen facial expression through the entire movie. Her character was really lifeless. And her powers were really confusing and inconsistent. She went around waving her arms at shit, and her hexes weren't really distinguishable from shooting energy bolts or something. Her powers were never really used properly.

Quicksilver was underused and didn't provide much. I liked the X-Men Quicksilver better.

The Hulk/Black Widow pairing was really weird and felt forced.

Hawkeye actually played a really good part in this one.

Felt like they were really trying to make Iron Man more brooding and conflicted. But it didn't come off quite right.

Ultron himself was pretty badass. His AI struggle to understand humanity was well done. But it felt like they didn't give him enough time to establish his plan.

Ohh, and there's a huge Mjolnir reveal, in a real WTF moment. Can't spoil that one though..... :D

They had a nice little grouping at the end, to essentially frame the future Avengers generation.

Overall, it lacked the fun teamwork aspect of the first one, and seemed more intent to focus on the individual differences of the members. Made it feel less satisfying than the first one. Like a sequel is necessary to tie it all together. Still a great superhero action flick though. And I will be seeing it again in the theater for sure.

Any Thanos appearances?

Only a reveal that Loki's scepter contained the mind gem, which we already knew.