Nine corpses at the least
Towards the end, the cast gave us a chance to vote for a happy ending, or an "every-one dies" ending. We were a small but vicious audience, and voted for tragedy, almost unanimously. Bad choice! There were only four people to kill, and they died in rather arbitrary, unsatisfying ways. (The seven-piece band remained untouched.) Perhaps the happy ending would have been more fun.
I mean, really, there's no point in killing everybody unless you can match or exceed the death-count in Hamlet, and Shakespeare sets the death-count bar pretty high.