This is really great, it reminds me of The Iron Giant, one of my favorite animated movies of all time. The ambiance is really great, the only thing I dislike is the cloning. Not just because copy-pasting looks lazy, but also because it absolutely wasn't necessary. The image would would far better to me if it just had one giant, to add personality and one balloon (I realize that wasn't cloned) for better compositioning.
Nonetheless, really, really great.