Scumm

A murder mystery set in the world of video games.
Life is hard and there's no difficulty setting.
It was especially hard for the man who was found murdered in his home. And in a city of crime, betrayal and deceit, who can you trust? And you can't look up cheats on the Internet either.
You play as Richard, a private detective investigating a murder but gets drawn into a tangled web of conspiracy and soon finds himself running from the law and the unlawful. It is up to him to solve the mystery and uncover the truth - but with only one life and no continues, it's not going to be easy.
Like I said, there's no difficulty setting.
There's not even a tutorial.