The mansion murder mystery is a time-tested genre. Its attraction seems to be two-fold: the mansion, and the mystery.
The mansion gives us a great territory with lots of plush details to set all sorts of intrigue: peep-holes, hidden passageways, floor-to-ceiling tapestries and curtains to hide behind, and characters who care what they wear, costumes with all sorts of pockets and linings and frills and folds to hide weapons and clues behind.
The mystery lets us scrutinize their character and rifle through their wallets, drawers, and closets looking for stolen jewelry and poorly-buried skeletons.
Three movies combine that attraction with an extra element of the games the characters play. The audience gets to play those games with them, but how the game is played and how the characters are represented say a lot about what the audience is supposed to get from the mystery.