There are better hi-res screenshots available at PlanetUnreal.com, including some nice wallpapers made from them

Guess it looks about as good as it can considering the limitations of 32 bit color?

A 2D jpg image of something that is "real" looks great as expected. Fire up Quake3 and notice it doesn't look very life like does it? The lighting is limited by 32 bit color: 8 shades of red, green, and blue each= 24 bit, other 8 for alpha/stencil. Need more shades before a game is ever going to look "real". Our monitors could handle any number of bits of color in a rendered 3D environment. A 24 bit "true color" 2D jpg is not at all like real time light effects in a game(which have limitations).