All instructions in-game, but just in case you forgot: WASD for character 1 movement, with SPACE BAR being the attack button ARROW KEYS for character 2 movement, with P being the attack button DIFFERENCE FROM CLASH OF COUNTRIES 1.0 The difference is that the attack is more logical so that it isn't random, but instead, it is according to your relative position to the other player.
Feel free to remix this project, but please credit @codingman333 if you happen to share it on the Scratch community.