After the extraction of PlunderHorizon_alpha4.rar and trying to start the game.exe, I get a systemerror which tells me, that the game can't be started because ucrtbased.dll is missing.
I uploaded a possible fixed build, plz try if it works now! (its called win 8 test 1). That one will only take you to the game menu for now, but it should possibly let you run it on your win 8 (starting a real game wont be possible just yet with that build, but lets hope it runs on your machine:).
The first computer I used was Windows 7, and had some stuff wrong with it already. I'm thinking that on the windows 10 it was probably a DirectX file missing.