It's looking like theres a penalty for being rated a smaller number of times. So if you didn't get many plays / ratings, your game is rated lower.

I really love your game by the way. Also, fun fact, if you weren't penalized for the lower number of ratings, your game would have the top score for the "Theme" category. My game, The Helmscrab,  has the top spot in that category. I remembered your game and went to see how it was rated, and I noticed the penalty as well, and that your raw score for theme is actually higher than mine.