As a fan of The Lost Skeleton of Cadavra and its sequel as well as Tales from the Pub, I also enjoyed this movie. I will say that all these movies are funnier in direct portion to the number of people watching at once. By yourself it is not that funny, but for some reason when you get about a dozen people or more together to watch, it is the funniest movie you ever say and you will laugh so hard you cannot breathe. If you saw it by yourself or with one other person and din't find it that funny - do yourself a favor and watch it with a group and don't give them any info about it other than you will enjoy it.
I have watched a few movies and plays and even read old books of the murder mystery at a mansion variety, and I think this is a good send off to it. The characters are larger than life and ridiculously overacted even as caricatures of the archetypes, except a couple of reporters who actually have a good repertoire and are believable as examples of the old archetypes of 40s and 50s reporters. If you can't stand overly-characterized acting, you will get annoyed at anyone besides these two characters, but try to not be overly critical and just enjoy it.