Being a "good" photoshop artist is not about how many filters or tools or layers you use. It is about how you create it and why it is.
I'm sure you'll figure this out soon,"The underlying game content that the screenshot is based upon cannot be changed, i.e. you can’t add or replace the underlying content of the screenshot." If you try to understand where HTC are going with this, I'm sure you'll create a winner in the artistic section of the contest.
Good luck Weazely!