Its a pretty great "asynchonous multiplayer" game as well - My friends and I had a server going for a few weeks and we'd log on when we could. Had a central 'mall' area, but everyone branched off and build their own projects which mined and manufactured items and sent them in towards the core. Was quite delightful to log in and realize your friend had built 100MW of additional power since you played the previous evening :-D