You have a lot of single pixels here that seem to not contribute any features or texture - they read like unintentional noise. Cleaning those up would help a lot in making this look finished.
Pixel art is largely about creating clusters out of pixels - single pixels don't actually tend to work well. When they do, it's always in the context of other clusters that give those single pixels meaning. If you have too many single pixels, your clusters lose their readability, and therefore their ability to give single pixels meaning, which is why it all starts to look like noise.
It is not a straight-nosed goblin xD (just joking.. ty for telling me.) Actually the mouth is in a different angle.. he is smiling weird.
The angle of the nose is different than that of the mask it's attached to.
thx for the advice :) I have to practice