In the future, click on the "reply" button so that I'm notified of your comment.  I just happened to look at my old comments, clicked on your piece again, and finally found your response!

Thanks a lot for the thoughts, guys!

@Macaroni and Cheese: Haha, your interpretations are reassuring to hear -- good to know I haven't totally missed the mark. The last one is a stretch though; I think an environment full of sloppy pixel work is more likely than pollution!

@failureboy: You're right that the screen is big for the detail level. I wanted a kind of vast, vaguely-cinematic look (word choice?) though, so I'm not sure if I want to change the canvas size. As for the colors, do you mean switching hues so the background and foreground are more distinct from one another? (E.g., gray hills and orange sky or something.) And yeah, desaturating might be in order.

I made a preliminary edit with a few changes -- notably I got rid of the sword health bar because, yes, it was really ugly.

The only thing I don't like is the Big Red Health Bar Sword.  It's ugly and your attention just goes right to it.  Plus, it's a sword, so a part of me wonders if it's about to swing around and be a part of the action.  I'd change the design of the health bar and put it over the boss, not in the middle of the screen. 

It's a forest scene, so I would expect foresty monsters. The boss matches the earth tones and greens you used in the background. It also looks pretty wild, untaimed, and dangerous. All these fit nicely.

The boss' left arm looks like it is bigger than its right. That seems unnatural and unhealthy, something I would expect in a polluted environment. I don't know, just thinking.