The first part after the intro will be the same but with Mr. Peterson being in his house
And when you get into the basement a cutscene plays where you find Aaron but Mr. Peterson comes behind you and gets Aaron before you, and then the police arrive cutscene plays.
Mr. Peterson takes Aaron forcefully and escape from the back basement door but he locks it
and then Quentin needs to escape the house you need to escape without getting spotted by the cops, as a tutorial to how to stealth
And then you go to the Museum where you find Mr. Peterson's car in front of the Museum
The shovel that triggers the nightmare 1 is standing near the car
Then rest of the game plays same
I think after the first house done, Peterson house is now inhabited by Nielsen and if you want to find more secrets inside the house (Add more secrets inside the house) you need to go against Nielsen