For starters, Unreal is drop-dead gorgeous. All of the 3D shooter frills that matter are presented in unprecedented beauty. Mirrors allow you to see your reflection in great detail. Colored lighting brings to life everything from torches to fluorescent lights. Steam and fog effects are so realistic that you can almost feel the condensation on your cheeks.
Transparent water flows in streams and drops majestically from high waterfalls.
But what's most important is the way that all this beauty was matched with intelligence. Rather than just wowing the audience, the designers made sure that all their hard work truly meant something. Disbelief is suspended, just like that. The first things you'll take note of when you leave the vessel are the birds circling in the sky and the rabbit-like creatures running along the ground. Perhaps the best thing about Unreal is the unabashed creativity that went into its design.