Brainiac
Super Freak
I honestly think that AOU suffered from the Infinity War hype train, especially since it was built up at the time when AOU still hadn't come out. I also didn't like how much they kept foreshadowing Thanos and the Infinity Stones instead of simply focusing on the conflict at hand. Not only did it sort of trivialize Ultron as a threat, it also made the movie feel like it was just a "part" of a bigger whole instead of being a story of its own that fits within a continuity.
I really loved how Spader carried Ultron and I thought he was terrific. I just wish there was more care put into how the narrative was handled and I would have preferred it if they gave Ultron more interactive dialogue/screentime with the heroes themselves.
BIG problem for the movie. I think they should have left out Ultrons 'Infinity' Origin in favor of a more comic accurate storyline and made him more menacing and dangerous and calculating.