This took me over THREE HOURS to beat so I recommend to anyone about to play the game you keep a pencil and pad with you to draw a map or write where things are, it's easy to get lost.
That being said this was an immensely satisfying end to the series with tons of callbacks to the earlier games. Puzzles were at times hard to think of but none were dumb or impossible. Art and the ambient music were beautiful. Biggest complaint is all the backtracking but that didn't affect me too much other than the part with the fuses.