WASD to move, get damage in by jumping on top of or too the side of the boss. You can combo by wall jumping on it, or land right on top of it to throw it. If it lands on you, you take damage.
This is an old project concept that I edited to share. There are a few errors, as you can only take damage when you are below the boss, and if you combo the boss for long enough, you can win without much effort.