Bought a copy of "Clue" (1985) at Goodwill yesterday. Definitely a cheap knockoff copy of the genre.
Fabulous cast though: Martin Mull, Michael McKean, Eileen Brennan (again), Madeline Kahn, Lesley Ann Warren, Tim Curry, Christopher Lloyd.
Unfortunately the script was sub-par, and the rehearsal insufficient for the cast to gell. Pacing was off, editing was off, there was no sense of tension building. Large parts of the movie looked like Keystone Kops, other large parts like a high school production.
The big "gimmick" of this movie was that they filmed three different endings, and sent different ones to different theaters. It hardly matters -- everything is so over-the-top madcap silly that you end up not caring a bit.