Bruges is definitely doable in two full days. Highlights include:
1. The Bell Tower (featured in the movie In Bruges). The 366 steps are not difficult to climb and I generally suffer from vertigo.
2. The Begijnhof. Arrive just before noon so that you can attend the service where the nuns chant acapella.
3. De Halve Maan Brewery Tour. Again steps on the tour. Or you can just sit and have a beer.
4. Chocolates, chocolates, and more chocolates!
Bruges is a very compact walkable city. We had dinner twice at the Gran Kaffee de Passage - some of the best lamb chops and ribs that I've tasted.
Enjoy!