A and D/left and right arrow keys to move, W/up to jump. Don't touch water drops, poison drops, purple poison balloons, or Watrme. Touch green water balloons to damage Watrme. Do not fall to the bottom of the screen. If you beat Watrme without taking damage, post it in the comments.
Thanks to @GoldenCart for Boss Battle - Oppostomp EX - Extra Boss 1.
