This looks good at first glance but so many features are disabled I have no way to make any useful assessment of it. The one bit that is claimed to be fully working - the Orrery - has a non-intuitive and non-standard interface (in my book, using an "Eject" button to mean close window is bad design - there are perfectly good controls built in to the OS for that, but here they've been deliberately circumvented! Also, "Play" doesn't, it single steps.). Unless the author gives more away in the demo/trial version, and fixes up the interface idiosyncracies, there's no incentive to pay the license fee.