Click the green flag. Player 1 - Arrow Keys to move, SPACE to change element and Down arrow key to shoot respective weapon. Player 2 - WAD to move, C to change element and S to shoot respective weapon. Each player has 10 Hit points and when that runs to 0 that player loses. You can spam. Fire beats Ice. Ice beats Fire. Also you can melee your opponent. Good Luck!
Comment if I should add joystick for the one of the sides.