Since we were also watching a movie at the time, the build time was about 3 hours but I think for most people, you are looking at 25 minutes or so. A few tips from this build:
1) Consider gluing some additional detail to the roof - or - sanding the four tabs that attach it to the left and right walls for a looser fit. It's hard to get any purchase on it when you want to lift the roof off to get inside and it's a tight fit, too.. so much so that even if you hook your finger inside the roof hatch, you will still have some trouble getting the roof off unless you pick the whole building up.2) We totally built the shelves the wrong way. That doesn't really matter, of course, but to build them the way Troll Trader have done, ensure that the two small shelves have the 3 hole shelf at the top, and the slot shelf on the bottom. Obviously they are designed to accept the two different types of swords but I didn't figure that out until we had finished.
3) Be careful when punching / cutting out the front of the floor tile - unless you don't mind having a gap, there is a very small piece of mdf that you will want to keep that will fit between the base of the left hand pillar and the left side of the door frame. You can see this pretty well in the first picture.
All in all, a fun little building although I think I've been spoiled by the two floor structures I've been assembling recently because it seems pretty small, especially with that flat roof. Still, you need somewhere to snipe from, or to hide from Graboids, right?