Triffid - Finished?

Here's what I have now! I have darkened it a lot, and it does look more improved. I'm wondering if I should call this finished or do some more work on it? So I'm going to allow it to sit for a bit while I figure out what to do next! Besides, I find when I've just finished working on something I never think it's that good - then after a while, I look back and think it's turned out much better than I thought it had!

Please let me know what you think! Constructive Criticism very welcome! :)