Uru is the latest installment in the Myst series of games (Myst, Riven, Exile). This one boasts full freedom of movement, avatars, and an online version that allows for interacting with other players. I downloaded the demo, and poked around a little bit. The freedom of movement seems to be accomplished by lowering the quality of the rendering. One of the things I really enjoyed about the other Myst games was the exquisite detail in the worlds. The Uru demo has that flat synthetic feel of texture-mapped 2½D worlds. I hope the full game will look better, the screenshots certainly do.