Hugo lauds the beauty, power, and magic of film in such a way that, as a lover of the medium myself, makes it impossible to hate. I feel bad picking any kind of nit about it, because it truly is a wonderfully realized love letter to celluloid.
However, there are some story flaws that keep it from perfection. The sharp turn in takes in the second act is a bit of a protagonist bait-and-switch, and most of the anticipated plotlines feel a little irrelevant.
The 3D for the opening half-hour is also incredibly gimmicky, often times forcing objects into odd places at the foreground to remind the viewer of the depth. Thankfully, Scorsese dials it back as the film settles, and the 3D becomes an organic extension of the film itself, much like the way Melies hand-painted color would have been in his time.