Complex sentence: That done, Frasier attempts to lift everyone's spirits with a party game, but everyone else is sullen, sulky and uncooperative, and it isn't long before more petty bickering breaks out.
Split into simpler sentences: That done, Frasier attempts to lift everyone's spirits with a party game. Everyone else is sullen, sulky and uncooperative, and it isn't long before more petty bickering breaks out.