At least i can say It has nothing to do with Windows 11, i played it a second time myself only a week ago on an Windows 11 PC, but sadly i can't say what causes your problem instead
Viewing post in Princess Reconquista / 王女のレコンキスタ comments
It is a windows 11 problem actually,
This is a problem that appears in EVERY Pixel Game Maker game due to windows 11 having all its DLLs updated to 64 bits and pixel game maker is not compatible with those 64 bits variant. this problem is not present in windows 10 or instances of w11 that have been previously in windows 10 so if you updated your windows 10 to windows 11 you wont have this problem