Building is an atmospheric surreal/horror game with puzzles that are loosely connected together. As far as tone goes, it is darkly romantic through and through. It won't appeal to puzzle fiends, but atmosphere junkies will find it more to their liking. Theme? The nature of the modern workplace, seen through a very cynical and mourning mirror.
There are no bugs that I'm aware of; the game is playable and winnable. The puzzles are fair and not difficult except for one, which is challenging. I designed it that way so as to not disrupt the atmosphere.
It is influenced by Babel, so fair warning would be if you don't care for that style of gameplay, you won't enjoy Building much either.