Hey Dirk, I'm the other half of Leadfoot Productions you haven't talked to in person :) The tile based system works better for some engines than others and the way I did it is generally better for a top down view in blitz due to blitz not being very keen on huge numbers of entities or surfaces.
Can probably get around many of blitz problems using some simple bounding box occlusion for each room, or triggers for doors that also allow the next room to be drawn.
Can probably get around many of blitz problems using some simple bounding box occlusion for each room, or triggers for doors that also allow the next room to be drawn.