Here's the two versions I own under this 'Escape From Singe Castle' specific packaging
On the left : IBM PC 5 1/4 disk version, on the right : IBM PC 3 1/2 disk version
If you don't count the stickers 'IBM PC/TANDY' and 'AdLib Sound' applied on the left one, the boxes are *almost* the same, I spot one difference... see
On the IBM PC 3 1/2 disk version, it's written 'made in canada'. It's not written on the IBM PC 5 1/4 disk version.
The Amiga version has a different packaging... so you obviously own the IBM PC 3 1/2 disk version.