Maybe you could have added a shadow on the floor... But overall, it is a great work.

Also, there's something about the green magic on the feet that seems a little off for me, I'm not sure what though, it doesn't feel like something that was planned, like if you just wanted to add more magic to the character. But this is just my very subjective opinion.

Amazing work, lighting is great. Just one thing, maybe you could add something to let the viewer know the scale of this place, you know, maybe a simple human silhouette or something...

I think that's very good for no line art. And two things that could help you:

1) Try drawing over and alchemy design thingy. If you don't know alchemy, Just google alchemy drawing software or something, it's free and very good to generate something that will trigger ideas.

2)I think you could improve on your values, more contrast on the main area you want to feature, and maybe darker shadows in general.