It might be a simple speed painting, but you've shown a significant level of talent and crafsmanship that you have as an artist. What you've shown has indicated two things: You have an interesting and illustrative approach to drawing humans and secondly you workings of the chosen brush and exploration of colour has certainly come along way since your humble beginnging.
With the anatomy, you've certainly shown that you understand it to a strong degree, but have taken the approach of designing them as caricatures rather than them being focussed on realism. You understand this route well and have shown that you can approach it with a lot of empathy, creating something that is appealing as well as slightly humorous. Though in honestly the way we see the character face on does leave her feeling somewhat flat, it might be that additional shading was needed or how certain parts were approached.
Colouring though is certainly another impressive point to make out. The way you've used just the one brush to apply the hues through various pressure has worked well. What's more is just the general way you've approached the colouring with your own personal ideas. For example the overlapping of certain brush strokes and such have all worked beautifully and left the piece with a real amount of energy.