Well, yeah, he does - he wants to kill all intelligent lifeforms on Earth, afterall.

Man can believe the impossible, but can never believe the improbable. Even a fantasy has to be grounded in its own rules.

This won't happen in this movie though. At worse, a few buildings will be damaged.

Ultron can adapt to new situations. You think they'll show the final battle in trailers now? Plus Ultron is the spark that leads into Civil War

I expect Ultron to be the first supervillan in the MCU to escape and live to fight another day. Even Loki never managed that, he was always captured and defeated. Only in Thor 2 when he was pretending to be a good boy and faked his death did he actually get away.

So being the first bad boy to determine the manner of his exit strategy is pretty bloody strong when you are going up against a whole team of super heroes.

You could argue Winter Soldier was the first, but he was defeated philosophically so that he turned from being a bad boy into good... or at least no longer a threat, ever. And we are pretty sure he becomes Captain America Mk 2 some time in the next few movies right?

At least I hope Ultron gets away. I really hope Hollywood doesn't go all Hollywood and has the bad robot get properly defeated in this movie. The MCU needs villains other than Loki to live to fight another day.

I'm thinking he's going to take the Mind Stone and bounce. Just go to space at the end of the movie. Then in Infinity War Part 1, he'll fight Thanos and lose, which is how Thanos will get that stone.

This is also a quick and easy way to establish that Thanos is even more powerful than Ultron.

On a completely different topic, if the Fantastic 4 re-boot flops do you think Marvel/Disney will be able to buy it back so they can bring the heroes (meh) and villains (yay) from that franchise into the MCU fold? Or at least do a Sony-like deal?

Well ultron has been defeated quite a bit over the years.
-Ultron-6 was tricked (by Pym) into self-destructing, destroying his entire body except for his head.
-Ultron-7 body wasn’t cast from Adamantium, making it somewhat easier to destroy. And, indeed, it was destroyed by the Fantastic Four a short time thereafter.
-Ultron-8 destroyed by the Scarlet Witch.
-Ultron-9 This one was knocked into a pool of liquid Adamantium which cooled, encasing him eternally in a block of the virtually indestructible ore.
-Ultron-10 destroyed by Machine Man.
-Ultron-11 Wonder Man tore Ultron-11 apart.
-Ultron-13 destroyed himself.
-Ultron-15 was destroyed by Pym using Antarctic Vibranium.

There is soooo many more. Ultron has been beat up quite a bit. The most important part of him is he's resilient. He finds a way to survive or he has a backup body. He's able to take control of people and robots, creating minions and bodies. Later on he finds a way to regenerate (heros of tomorrow) and he defeats a lot of people.

I think Whedon felt the need to dial Ultron back for Avengers 2 to avoid any Deus Ex Machina cheats to allow the Avengers to miraculously defeat it.

Writers can make Ultron all but omnipotent if they so choose, but the challenge comes in making Ultron a complex character that has exploitable flaws that will lead to its defeat by the protagonists.

Unfortunately, we will likely be seeing the Inverse Rule of Power in effect, which simply means the more drone/clone/minions Ultron spawns, the weaker and more disposable they will be (see Iron Man 3 and his 30+ disposable armor suits). Looks great on screen though.