I am looking for the title of a sci-fi/ horror movie, I believe from the 80's... It's about a guy in his house where he dreams he commits a crime... But it becomes real... There is someone scary looking who talks to him... I think it's dream something, but not dreamscape...

Maybe Brainscan (http://www.imdb.com/title/tt0109327/)?

No, this was very low budget... from the 80's... the character that appeared was kind of like David Bowie in Labryinth... at the end, it was all a dream... dream something...