The game is currently in Early Access Alpha for $15 on steam, dunno if its offered outside of steam. It's starting out eerily similary to minecraft, only a creative mode is available right now with a lot of functions ready but disabled while they tune it up. Also only singleplayer is available right now and they have yet to add a substaintial map generation system as there's nothing but void shortly after leaving the comfort of the asteroids you spawn near. But the devs are working on multiplayer and a survival mode. I could easily see this game having randomly generated space entities such as asteroid belts and planets, and maybe even missions. They've even got a mild amount of lore creating a point in time which the game takes place (loading screens have quotes describing Space Engineers that come from their year 2077 Wikipedia). It has an enormous amount of potential. It's physics and collission engine are incredible but don't cause problems for computers within the recommended specs until you build absurdly large ships (and as it stands that's the only thing limiting your build sizes, how much your computer can handle or when the game runs out of memory for entities). Already having fun with the various building options and crashing the default ships into each other. Looking forward to future updates, they just changed landing gear so you can magnetically stick smaller ships to larger ships (so they don't bounce around and get destroyed if they are in a hangar bay or something during transport) or you can latch on to another ship and tow it.