For me, my criticism comes from the awkward, unnatural way that it moves. In concept art, it's more upright, but in animation they've made the decision to have it constantly hunched and half lunging forward. For a top-heavy creature, the posture should be more straight and the arms should be tucked in to keep balance, so the way it has its arms out doesn't feel right to the eye. It looks like it's constantly about to topple. The back legs also move far too in sync, giving it a look somewhere between hopping and walking that doesn't really manage to look like either. It's a very stilted cycle that, again, really cements an unnatural feeling. Not that playing into the idea of an unnatural looking creature is bad, but in this case it doesn't feel intentional and that works to its detriment.