Constructive critique? I shall do my best!

I do want to say, first off, that I like your use of grey for the shading. It looks like you started off with grey as the base for her and built up your colors and details from there? Not enough artists do that, IMHO!
I also want to say it would have been better to have chosen at least a slightly different color base for the background. As it is now, your main focus could stand out that much more than it already is.
Perhaps the grey was relied a little too heavily upon, I could see a few more 'highlights' added, especially to the right of the neck there.

Anatomy-wise, the first thing that struck me as odd is the mouth-area, particularly how small the bottom jaw is incomparison to the top. If I imagine this reptile to close her mouth, she would have major, ah ...overbite? As in, too much so, you know?
The teeth are another thing; They just seem a little too simplified, and perhaps too small as well.

The background is indeed quite simplistic, but it almost lends the feel of a photograph. I kind of like the look, myself, but again it might have been better to have chosen a different base color for that area other than grey.

Ah, that's all I can think of, for now. I do like this!! Hope at least some of this was helpful.

thank you! D: i was afraid no one would give any critique on this.
it was my first time trying the grey scale first and i do rather like it but i still need to learn how to shade properly, highlights etc. alot of the furry types seem to say they can draw humans, well im the opposite in i cant seem to draw a decent animal head x3 and ill deffinatly make the back ground a little less boring next time too
thank you again for lending your opinion! i appreciate it

time for a non artist and pointless fanboy response, HOLY CRAP KARN THAT LOOKS AMAZING....never seen Leelee in a feral form drawn like that its just......wow

Wow, that's neat.

Noice, i like the lighting. I can definitely see your colour work improving, and communicating more of a style