The skill level system in Kongai ranges from level 1 to level 50, and players can only rise in level by defeating opponents in ranked matches. Losing matches, however, will cause a player's level to decrease. Your skill level in Kongai is basically just a simplified number representing the number of "rank points" you have.
Defeating someone equal to your skill level will yield 100 rank points, defeating someone 10 levels higher yields 144 rank points, and beating someone 10 levels below you will only gain you 56 points. Losses to those same opponents would lose you 100 points, 56 points, and 144 points, respectively.
However, if you are skill level 28 or lower, the penalty for losses will be softened. You'll only lose 10% of normal at level 5, 50% of normal at level 10, 77.5% at level 20, and so on. Once you reach level 29, you'll lose the full number of rank points with each loss.
On the flip side, if you're super awesome and reach level 42, a similar system kicks in to penalize your wins. You'll only win 95% of the normal rank points at level 42, 80% at 45, and 55% at level 49.