Here is the full list of all 12 Murder Is Game Over achievements.
Pet the cat, either as Cleo or Guy.
Play the arcade mini-game and beat the boss monster.
Approach the bear in the woods.
Cleo plays a song on the pipe organ.
Avoid getting hit by falling debris in the castle basement.
Speak to the community college gaming club member in the cemetery.
Open the door leading to the roof, which was forced shut.
Speak to the fireman who is barricading the press from the crime scene, on the mountain road.
Get the good ending where you find 30 doggie bags.
Get the good ending where you find Herr Ludwig's treasure.
Find the little mouse that is responsible for the moving armor.
Identify the guilty during the denouement