There were a few things that bothered me, though. I often wanted to shake Hugo (and other characters) and yell "just tell the truth already! why all the secrecy?" Also, I didn't have a good sense of how much time was passing. For a book that relies so much on clocks, you think it would be more obvious - but I guess that would depend on calendars, not just a machine that counts the hours.
I know the "Invention" of the title is supposed to be his automaton, but I wonder if it also refers to the invention of Hugo as a person - how his skills and interests are finally given an opportunity to flourish once he gets involved with Papa Georges and Isabelle.