This is the free demo version of alpha 0.72, it's got several hours of story mode and the build mode.
For users without opencl compatible graphics cards due to whatever reason (outdated driver, unsupportive manufacturer, incompatible setup, etc.), please go to options in the launcher and change to cpu under opencl calculation, then launch the game. If your game hangs at 100% or fails to load, it’s most likely due to opencl.
If you enjoy the demo, please tell you friend about it and preorder the game here: Planetexplorers.pathea.net