The main effect the developers were going for in Lifeline is that you're watching everything through the ship's security cameras. This effect is handled really well during the game and is successful, but to a point. At certain points in the game, the camera switches to a more cinematic view, which kills the immersive atmosphere. Overall the game doesn't look all that shabby. Rio looks and animates rather well. She even goes through an appearance change during the game, which is a nice detail. Much of the game suffers from a lack of detail, but this is forgivable since it not only fits in with the game's overall style, but also the gameplay. A big part of the game involves describing elements in the room for Rio to check out and interact with. In some cases the lack of detail is helpful since you can say 'Check Blue' and she'll know what you're talking about. In other cases it is a hindrance since there could be two 'blue' in the room, forcing you to really think about specifics.
For a game based solely on voice, Lifeline certainly is quiet. Background music is virtually non-existent, except for a few ambient sounds here and there. The biggest draw to the game is Rio's voice work, which is provided by Kristen Miller (of She Spies fame). The amount of dialog featured in the game is staggering and is really well done when you consider the conditions the game sets up. All of the communication in the game is given to you through Rio. This includes things like reading a newspaper sitting on a desk or what is displayed on a computer terminal. Once again this helps to set up a great atmosphere. Rio also responds to all of your commands, as well as yelling suggestions, cries for help and a few smartass comments. Yeah -- all you jokers who think you're going to be really cool and start flirting with Rio or telling her to do stuff are in for a few surprises.