It's pretty basic. A series of metal floors, gratings, control panels, and the like. Good for doing a futuristic building, spaceship, or station. And you could always mix it with the other tile sets in order to do planetary stuff.
I've been using them to build my Final Fantasy I conversion of the "Sky Castle."
I have seen them (they are called Galaxy Tiles, I think) in store a few times, but since there is only that one set, AFAIK, I could resist the temptation to see what they look like, because a single set seems hardly that useful to me.
Here are some pics of the Dungeon Tiles Master Set: The Dungeon. At the top of the second picture are the box and lid, which are also tiles 1 and 2 inches high.