You have 9 colors in total here, when it could really do without most of them. About every 3 of those colors are so so close in hue range, it makes it a bit pointless in using them. Might be wise to pay attention to this in the future.
Needs some AA and a transparent background. Other than that, its good :D
Listen to The B.O.B.. The majority of colors here are completely redundant. You should really be careful with how you pick and use your colors in pixel art. It feels like you used a semi-transparent brush in Photoshop for a few pixels there.