Read this if the game doesn't load.
Battle Over Berlin
Fly the plane and then try to shoot and/bomb the opponents war plane to win the game. Speed up plane using Up arrow or W and then press Left Arrow or A to fly higher.
Player 1: Arrow Keys to Fly < and > keys to fire gun and bomb respectively.
Payer 2: WASD to Fly, C to Fire Gun, and V to Fire Bomb.
Related; Into Space Hacked