Sometimes you might have the feeling that your opponent plays inhumanly well. In most cases your opponent is simply a strong player, but sometimes you face an opponent who's using a chess engine. An engine is a computer program that analyses chess positions and recommends the best moves. Using an engine is strictly prohibited and in most cases leads to suspension from the Playzone.
If you think you've found a cheater please report the game by clicking on "Report" in the game menu.