Gemini Rue seems to do a good job of blending two different feels based on which of the two main characters you are controlling. When controlling Azriel, you will find yourself primarily in gloomy surroundings on a planet that is under perpetual rain, meanwhile, the parts of the game that have you controlling Delta Six put you into bright and white-washed locations with a noticeable, slightly futuristic feel. As a result, the game blends both noir and science fiction together in an interesting way.
As for the sound, there were times when the voiceacting felt a bit too forced and the characters were just too stereotypical to be fully appreciated. While Azriel's segments were distinctly noir, I constantly felt like the character was going to break into a bad Bogart impersonation. It just wasn't quite right.