Mirror Match (Donitz)

Mirror match was intended to be a js1k.com entry, but due to the size limitation I believe it's an impossible goal for this game. The smallest size achieved was ~2330 bytes, but the game logic can only be cut down so much.

The gimmick of the game is that the enemy AI mimics you. It finds the best matching mirrored state of the board, and does what you did in that situation. Can you go 20 rounds against your own tactics?