Lots of fighting and intense scenes throughout.
A character makes a comment about a failed suicide attempt.
The Chitauri and their leader, the Other, are extremely scary, especially for young children. Though they typically wear armored masks, one Chitauri rips its mask off at one point, revealing a disfigured alien face.
Though the film may have scary disturbing and creepy characters this film can be light hearted probably one of the most light hearted movies made by marvel
The Hulk chases the Black Widow, causing massive destruction along the way.
There is a few scenes that could definitely frighten younger viewers, but nothing too crazy.
For tweens/teens.
Multiple casualties during the battle of new York. We don't see the casualties but there heavily implied.
Natasha Romanoff/Black Widow is kidnapped early on; The kidnappers almost throw her into a hole, but she speaks up before they do anything.
There are several prolonged and intense action sequences, but they're not shot in an overtly horrific or graphic way, and there are also many comedic moments throughout the film that lighten the tension.
Bruce Banner has many scenes where he is apparently getting emotionally stressed enough to transform into the Hulk, and all the other characters show obvious fear of that happening.
The alien master known as The Other is very scary and disturbing.