As a Tex Avery fan, I must say that this is one of his best cartoons. There are a lot of great gags and jokes that poke fun at the mystery theater genre. The detective even goes to extreme to get everybody not to go anywhere (including breaking the fourth wall to knock out an audience who's switching his seat!).
My favorite part in the film? The red "skeleton" joke- funny! Tex Avery himself gets into the chaos by voicing Santa Claus ("Listen, bub- CAN'T YA READ?!")- the mystery genre was definitely served by Avery.