maybe it has something to do with your screen resolution?
thats a bug on my side, i forgot to set some things regarding the UI elements so the resolution is too small. is it possible to get a higher resolution on your monitor? if not than atleast try changing the resolution to any other which are possible for you until you can see and reach the start button. if it doesnt work then just delete the game, it was made as a short april fools joke so theres no reason wasting your time over this.