Am I the only one would finds it hard to believe this (Possible Spoilers

First off, I did find the movie entertaining, though nowhere near as good as the ultimate avengers movies, but I have trouble believing Ultron could do what he did. Do I think he could have killed Cap, Widow, Panther, etc. yes since they were more or less normal humans, but Thor would never let his friends die especially if they had young kids and Hulk definitely would have fought a lot sooner. And even if it could do those things, your telling me magneto wouldn't just come waltzing up to the tin man and crush him into a ball, or Wolverine, who was an avenger, wouldn't have sliced off the head of Ultron. Ultron had a shrine of all the heroes he defeated so I'm assuming not just the avengers were targeted, but there are a few Marvel heroes that could have easily disposed of him without breaking a sweat. But thats my take.