You must kill the knight. This level is boring, the knight comes after 26:40 and there is nothing you can do to speed that. I add an additional challenge to myself, guess what it is ;) Anyway you can skip this level, I just kill the knight with boulders. Incompressible time is 1600 sec (26:40)

As you can see I'm very good at ignoring room flags -_-' I do 14 tiles lair to avoid dragons