I've played the currently available Re-Mission. For a free game (they don't charge to download and play it, so feel free to find their site and try it yourself) I was surprised at the generally high production values for this game geared for kids. Nvidia even has an SLI profile for it.
It is relatively simple to play; it appears to be inspired by Inner Space and similar movies and concepts, and doesn't really come off as any more gross than being inside The Many from System Shock 2.
In the game you help different patients with different types of cancers who are not responding to normal treatment and need a special nanobot treatment (which is where you come in, as a player.) These virtual patients, their cancers, and the treatments are described using medically accurate language, so cancer patients should recongize the terms used.
I think it is great they are coming up with another version of this type of software.