Opening sequences in horror films

What do the opening sequences in other films look like?

The opening sequences in other films are conventional with the horror genre. They introduce the main character or main characters and then over time the suspense level increases. Finally, they introduce the killer to the audience by scaring the main character or characters. The same formula is used for every single horror movie ever. 

How does an opening sequence reveal the meaning and tone without giving away too much?

An opening sequence can reveal the meaning and tone by multiple things. If there's a high pitched music playing in the background, the tone is suspenseful and scary. If there is a low angle shot of a character, the character feels powerless against the monster meaning that the tone is also scary and frightening. If you hear stereotypes of a certain group, country, or person, you know the meaning of the film.

How much action really happens in the first 2 minutes of a film?

In horror films, the opening sequences generally have a decent amount of action in them. The opening sequences usually have action towards the end of the opening sequences. The action happens when the characters are scared of the killer and the characters are trying to run away from the killer. Most of the time, action happens for a minute in horror film opening sequences.