I live in a high-rise and our apartment is at the end of a hall. Across from us and one apartment down there is a family with children (well, pre-teen and teen now but still kids at Halloween). We decorate outside our doors for Halloween, Thanksgiving and Christmas (me)/winter (them). One year the man directly across from me was away the whole month of October so we did his area also. Our best touch - yellow crime tape across his door.
Our building has a party for all residents and the woman in charge, a professional caterer who lives here, does the most wonderful decorations. You might reach for a piece of food and a hand will move in the bowl, eyeballs could be mixed in, stuff like that. You either love it or you don't. I usually lend her my Halloween quilts for the entrance to our building's community room.