Hi guys how are you? how do i play with the dark boshy?

Beat the game on Average-Mode while collecting Awesomesauce, Mixer, Rupee, Timer, Cake, Scouter and Metal Gear. You can unlock him in the Prize Room after beating Solgryn.

Or you go to the "Resources" tab on this page, download the onlinelicence.ini file and put it into your Boshy folder.