Let me start off by saying that I somehow missed that this was not exactly the whodunit mystery I was looking for. And... I think I'm glad? Even though I'm still feeling a little disturbed two days later.
Compelling, I think, would be a good word to describe this game. Enough so that I kept playing, even though I really, really didn't want to once I started to suspect what was coming. Very effective. Even if I had to read certain parts with my eyes closed. No guess the verb issues and vivid (too vivid, gulp) descriptions.
I ran into a few places I got stuck. (Spoiler - click to show)I didn't realize the window in the bathroom could be opened. And the gasoline evaporating after three turns almost forced me to reload, but fortunately I had just enough "undos". The walkthrough for the original Mystery House gave enough pointers for me to get through.
Overall, it successfully tells a creepy short story while allowing the player to gradually discover the scope of that story through his own actions and the actions of those around him.