thank you!!! that's really helpful feedback :)

not bad, not bad at all
adding a bobing or sway to the arms will make it look much more complete though this post is quite by now so I'm a bit late

using transparency in pixel art is seen as a taboo people (especially long time pixel artist) much prefer to use their colors to give the illusion of transparency
adding transparency to a simple sprite like this won't change much but, in a more complex scene it will increase the color count significantly just something to be mindful about