I guess I'll write a critique while my premium membership still lasts (today is the last day, since I'm going on hols with no internet!?) so here we go:

This captured my eye when I first saw it in my news feed, probably because the colours are really bright and saturated, but also because of those eyes. Those large shiny eyes, commonly used in a typical shoujo manga, you've recreated for Gumi in anime form. She's cute, but the eyes really are overdone and affect the piece hugely.

I have to agree with you about how you're in a colouring slump because it isn't your best so far, but clearly it's not bad either. I like how you coloured her clothes, but the eyes and hair seem to have changed in a slightly negative manner. I really like the simplistic background though, especially the reflection because it makes the floor look really shiny! Clean shiny glassy floors we all love, so nice work there! Gumi's shadow helps build up the shadow, which is nicely done.

Well, I do think that she resembles Gumi. It would have further distinguished her as Gumi if she had her signature goggles, because if you hadn't said so, we could've just assumed it was any old girl with snazzy green hair Oh and one last thing, the anatomy is pretty good (as usual) but her arms look a bit too short; even if it is at a different angle, it looks a bit odd. Sorry if the critique sucked, I'm still getting used to writing them~