Am I wrong to say this was underwhelming without the actual ability to solve mystery?

First off, I enjoy a murder mystery that allows for the audience to have even a possibility of guessing the murderer/outcome. When there's backstory and such deep history, it seems to alienate the viewer for the sake of shock factor. I'd prefer the chance to guess whodunnit not be in the dark for a good chunk of the film.

The cast was fun, albeit a bit large a group for not everyone being important. Many of the characters just sat there, chimed in at their assigned times but had no depth or intrigue. I wish we'd seen and heard more from the supporting actors.