Space is an immensely huge, possibly infinite, location which is comprised of the space between physical masses. With respect to games, the physics and scope of space are generally neglected or ignored, due to the limitations they would impose on the story and experience and fun. Proper gravity rarely applies in videogames, and almost all space games feature sounds in the vacuum, an impossible phenomenon (and let's not even get started on fire and debris!). Space can be divided into two obvious variations: Intrastellar and Interstellar space.
No, this has nothing to do with Innerspace. This is the spatial area containing stellar masses including stars, planets, moons, gas clouds, asteroids, and other celestial bodies. This is the area of space most often included and portrayed in video games due to its relative complexity compared to the rest of the universe. Some prominent uses of intrastellar space (both realistic and fanciful) are in games such as Super Mario Galaxy and Descent: FreeSpace - The Great War.
The more neglected deviation of space, interstellar space is usually left out of games due to its immense scale and lack of much physical matter. Although it is BIG, it is also very empty.
Interstellar space is full of celestial objects, such as the stars, red and brown dwarfs, normal main sequence stars (such as The Sun), red giants, and the rare, but well-known, hypergiants, black holes, nova, supernova and hypernova, star remnants such as neutron stars, and millions upon millions of galaxies, all in our observable universe.
Space in Games
Interstellar space is a now common subject to some video games, such as the Sins of a Solar Empire, Mass Effect, and the popular Star Wars series. Traversing interstellar space is usually tackled through use of hyperdrive or other such devices in the context of a game's story, while it has also been thoroughly ignored through use of galactic maps or other such things in games like Star Wars: Empire at War.
Combat in space is essentially like combat on Earth, according to our games. Ships bank and turn, explode, and in some cases use foils and rudder-devices to steer the ship or close them to accelerate. They share a strong similarity with air combat games like Ace Combat, especially for games such as Star Wars: Rogue Squadron. Excepting dog-fighting in and ship-vs-ship, there is very little else that seems to happen in space.