I have no idea what isatche is going on about, I think they are very good and quite apt for the purpose described.

The only change I would suggest is the pose of the males. They way they hold the staves looks very uncomfortable and unnatural, particularly with the other arm hanging straight down. I'd suggest holding the staff upright with its foot on the ground.

What are you talking about? From this piece, you can instantly recognize my ability to draw? I admit that there are probably some anatomic issues with the characters, but you must have psychic powers to recognize 'major problems on the artistic aspect' from such a small piece.

Style isn't necessary, and the person who asked me to make these asked for a chibi, simple witch and wizard, so I don't think she would have appreciated two impressionist paintings instead of simple sprites.

I can see that you are detailed person, but two things are the major problem here and they are both on artistic aspect. First, you need to learn how to draw. Not pixel art, but real drawing. Second is that you don't give any artistic touch to your work. I can see nothing that makes it 'special' and easy to recognize. But from the technical aspect i like it. I can see that you really handle pixels well.