I think the strongest part about it is the unique character, but it's hard to make out because it seems kinda blurry. This could have been because of the way it exported, but it could also be that it was drawn at a low DPI. In digital art you want to be doing your covers at least at 300 dpi, and even up to 500-600 if you have very painterly brushes. It makes your computer chug, so don't do it unless your computer can, (like I do 300 most of the time) but you'll notice a huuuuge difference in your detail work once you give yourself more space for your brushes to do their job.
The other thing you may want to work on, is that only the yellow is standing out. This is becuase it is one of the few light shades here (the rest of the cover is a similar shade) and it's also one of the few colors that isn't closely related to that brown. By seperating your colors and making more of a balance between mid tones, light tones, and dark tones, you can make a much more readable cover.
Overall though, covers are hard, and I can tell you've done lots of work here, so keep at it!
