So, I'm the sub-developer of that game and truly do not agree with the score given to me.
The score was not given to you. The score was not a scoring of the game. The score is an arbitraryliy calculated number to rank the game in the jam. It takes the ratings and number of ratings into account. You can disagree about this all you like, but there has to be some measures to compare a game with 2 ratings against a game with 200 ratings. Something like "fairness" cannot come into it, since the developers do not even have to meet the same critieria in expericence. This is not boxing sport where you have a weight category to compete in. Or what about developers that already have a lot of followers. Naturally they will have more people checking out and rating their game. Mabe even rating the game up - or not, as fans can be more critical to your works than new players.
Whatever method you will use, there will be always people thinking it is "unfair".
some devs who uploaded their games will always ask to rate their game and give a score of 5*. That's unfair!
Uhm. Why? Seriously. Why? It might be seen as begging, but why is it in any way unfair? Is this some unfair advantage if you ask players to rate the game? How so?
Why does a game with poorly designed UI elements, and almost no gameplay
Maybe because it was fun to the people playing it? Being pretty or having advanced game play is not the sole criteria to having a well liked game. Look at Cookie Clicker. A self proclaimed non-game. You click a cookie. How is that gameplay? Or a kinetic novel! You click next. That is not game play.