You get 45 minutes for the demo, and you can start again anyway. The game is being made by David Braben who also made Elite. Chris Sawyer is involved as being an advisor. The engine is pretty good, with realistic water, and plenty of lights all over the place. The 3D is quite detailed apart from the peeps. You can add your own MP3's to the rides. You can build a coaster and ride it, and you can ride all of the other rides as well. You can watch the peeps, and they have amazing AI. They will actually walk up to each ride, and sit down in a realistic way. The will walk around as a family, and argue about which ride to go on. They will insult the entertainers. Entertainers will dance around, play dead, and a scarecrow guy will take his head off, and bounce it off an onlooker.
This game is top class!