Hey hey! Sorry my reply is a bit slow >.< I’ve been away from my PC recently, so I only just saw your comment.
Hmm, that is very strange >.< I haven’t had any reports of anything like that before, so I’m guessing it maybe is something weird with your computer, but you never know! It could just be something about the game that your computer doesn’t like for some reason.
Unfortunately, I’m not likely to be of much help because I’m not a very techy person :( I use Naninovel within Unity, and I test on my Windows PC and my Windows potato laptop, and if I can’t replicate bugs on either of those, I never really know what to do to help if someone is having an issue T_T
What is it that you clicked to launch the game? Because you shouldn’t actually have to install anything to get it to run. You just download the file from itch, and then after extracting the file into a folder, there should be a file in there called ‘Darling Duality - Demo.exe’ and that’s the one you want to click on. After double-clicking on it, it should just launch the game.
I have no idea what would cause a pentagon shape to show up because I don’t think any of the Unity splash screens use a pentagon, and I only use diamond and circle shapes within the game’s assets >.< So it’s a bit of a mystery.
I’m sorry I can’t be of more help :(