I backed this on Kickstarter when it was announced, so have been able to play it (maybe "playtest" would be a better word) for the past few weeks. It's an MMORPG with amazing potential, some of which has already been realised. Its physics is far beyond anything you'll see in any other virtual world. It does have actual gameplay, though, plus building, crafting and gardening. There's a skills cap (which unfortunately I've exceeded by four), so you can't do everything yourself; an economy is therefore waiting to happen, once players have acquired enough money from doing missions that they have some to spare.
Building uses both blocks and panels, which can be freely mixed together. Components are put together from materials extracted from the environment. These have different properties on different planets, so the iron on one planet may be objectively better than that on another. Although plants regrow, minerals don't, so there are two comppeting pressures at work: stay where you are because it has a wide variety of great plants but is mined-out; move to another planet where there's more, possibly different minerals, but the plants might be inferior. The game's message is one of the responsible husbanding of resources. This threads right the way through it; ignoring it is why I have more skills than I'm allowed (although to be fair, it would have helped if I'd known there was a cap before I took them).
Overall, Stars Reach is definitely early-access quality rather than the finished article, but it's still a blast, and there's much, much more to come.
Only after I'd constructed it did I realise that my house looked like a half-submerged TARDIS.
I've since put a blue light on top.