Is it me, or is the compass in UUI broken? When I move left on the map, it points "east", when I move right it points "west". However, when I move up it points "north" and when I move down it points "south", just as I would expect.

It works, but you are not thinking right. The compass points to the north relative to the direction you are facing.

Thanks, just figured that out. I expected it to work like a "game compass", not like a real one...

Older games generally had compasses that worked like real compasses. Some current ones in the older style, like the Grimrock series, also do so.

How else would it be supposed to work? The only other method that I could think of is displaying the direction you're facing. Like N, NNW, NW, WNW, W etc.

Well, a lot of games, if not most, simply show the direction you are facing. Lands of Lore for example displays a compass, but the needle does not point north all the time, it points in whatever direction you are looking,