You really have to visit this place, but you can always visit it in less than 12 hours.
Usually, I hate that attitude of seeing cities at a glance because I like to feel like I am living in a city. That is my traveling philosophy, after all. However, if I were to choose a city in which I could only stay for a few hours AND seeing I am already in a region surrounded by similar cities, my choice will be.
It’s a beautiful city. It has nice parks like Minnewaterpark in which you can sit down for a moment, see birds and nature, old buildings and not to mention the canals (despite it’s touristy and such, it’s worth taking a boat around the canals) and of course, the chocolate there. Still, if you have seen two Belgian cities, you could say you more or less know Brugge.