Disk.io

This is one of the very simple free online games. Here, you are on a field with another player (of a different color), trying to knock on their gates. It defends them (although not very rigorously), so it is possible to beat a medium level with the first or second try at most. The levels are structured in a way that they consist of several sub-levels and end with a boss fight. Note that the boss is not a very easy guy - he can capture his ball and aim it at you to hit his doors as well. When your gates are destroyed and the ball hits an unsafe area behind you, you lose the round. So be nimble enough to catch the ball and turn it to your advantage. Good luck playing this free online game!