because in the cutscenes the screen goes completely black and at the end it only comes back when everything is over (I feel like the game is censoring itself)
if you're playing the latest version(v0.13) then it definitely seems like a bug with your PC.
I would suggest deleting the game and downloading it again, but make sure you backup the save files in "C:\Users\[USER]\AppData\Roaming\RenPy\WorldTamer" first
