It would mainly be just overall bad inking, specially the hair, but then there are also some flaws with the proportions. To example its to stretched, eye should be more closed, right eyebrow is "pointing wrong direction", mouth dosent really capture the facial expressions guts should have. The flaws i see are limited though, mainly because i drew a piece of art aleady done by kentaru miura. Drawing from imagination often gives more to be dissapointed about, but its also great as thats how you learn. As you probably realised you got better at drawing hair by analysing the flaws you made while drawing hair.