Phantasmagoria (Roberta Williams')
When Adrienne checks the envelope in Malcolm's mailbox, the sender of the letter is R. Williams from Oakhurst, which would be Roberta Williams, the writer and designer of the game.
Bob Thomkins, the real-estate dealer with a bad attitude towards women, has posters of women behind his desk which are screenshots of the babes from Leisure Suite Larry 6: Shape Up or Slip Out.
When Adrienne has finished taking bricks from the fireplace in the study room, the hole looks anything but normal. It in fact resembles Sierra's Halfdome quite a bit.
In the nursery, click 4 or 5 times at a fast pace on the baby's picture. Her eyes will glow and an evil laughter can be heard.
In the bathroom, click 7 times on the chair next to the toilet, and then on the toilet. Adrienne will go to the toilet as usual, but sounds of farts, diarrea and a sigh of relief will be heard. This Easter Egg only works if Adrienne has not gone to the toilet yet during the chapter.