A few times during the movie reference is made to a Black Mesa research facility. Black Mesa is the name of the facility at which Gordon Freeman works in the Half-Life series of video games.
George Almore's car is a classic Lotus Esprit S3.
The outdoor shots from the falls are from Månafossen, Norway.
In one of the opening scenes the song "St. James Infirmary" can be heard in the background. It is a song about a man seeing his wife/girlfriend stretched out on a table in a morgue.