It may be a little too early to ask, but once some of you have finished the game could you please tell how long it took and how difficult the puzzles were? I was very interested in this but this review completely put me off : http://www.gamefront.com/lucius-review-murders-that-make-you-want-to-kill-yourself/

It depends on how fast you get the puzzles solved. If you are good at that you can complete the game within 3 hours. However you won't need more than 5-6 hours, even if you don't rush through the game.

Yes, it really depends on how good you are in solving puzzles.
The game has 18 chapters.