Delete this file. I think that might fix it
%Localappdata%\Stuffers\Saved\Stuffers_PCD3D_SM6.upipelinecache"
Disregard my previous reply, I realized I could copy and paste Stuffers_PCD3D_SM6.upipelinecache into the file search function to find it, and the game works again after deleting it :)
It was a very cool and nice tech demo for this unreal engine setup you're making, and I look forward to seeing what you do with it!!