The first trailer for Avengers: Age of Ultron set the tone for the film — darker, more sinister, and more brooding than the first movie. This trailer is, if anything, even grimmer. It's set to piano keys playing a macabre, stripped down version of Pinnochio's "I've Got No Strings."
The new footage show the Avengers at war with each other, and when they're not at war with each other, staring sadly, hopelessly into the distance. Like Captain America here:
Captain America (Marvel)
And Bruce Banner doesn't look like he's in the best of moods either:
Mark Ruffalo as the Hulk (Marvel)
In terms of the action, we see Thor get a bit more spotlight, and a chance to showcase some weather-manipulating (lightning) abilities:
(Marvel)
As well as the Scarlet Witch seemingly knock out Iron Man: 
(Marvel)
There's also a bit more of the Hulk and Iron Man (in his Hulk-buster armor) going toe to toe: 
(Marvel)
What's largely absent from the trailer is Ultron — the sentient robot with daddy issues who's the key villain in the film. A lot of the fighting looks to be internal among the Avengers, rather than the Avengers teaming up against Ultron. The few moments when Ultron and his robot army do flash on screen they look to be tearing through the heroes with ease.
