Here is the full list of all 17 Who Pressed Mute on Uncle Marcus? achievements. It takes around 3-4 hours to unlock all of the achievements on Windows.
Accuse every suspect.
Accuse Toby.
Praise mum too much.
Accidentally come clean about cheating.
Accuse Mum.
Accuse Bradley.
Accuse Lottie.
Answer that Lottie's biggest fear is baldness when playing with Nan.
Accuse Aunty June.
Accuse Nan.
Find the killer.
Saved Uncle Marcus.
Mum fools Toby into showing empathy.
Don't be persuaded by Toby to submit the wrong answer.
Don't be persuaded by June to submit the wrong answer.
Start the quiz.
Uncle Marcus reveals he has been poisoned.