Why it becomes more and more dificult to improve the score?
The rating system, as explained in rating.html, has been built to give good information about the skill level of players. You have to take int account: • Your score increases more when you win against players with higher scores, and it will be more reduced when you lose against players with lower scores. So, normally the score increases quicky during the first games, but it becomes more and more dificult when the level is high. • Players with high scores tend to be good players, specially because rated games are only available to players who pay for using Ludoteka and they usually are very competitive and play seriously. Obviously, playing against good players the chances to win are lower than playing against inexperienced players.
