Haha, well done matching my highscore! It is not easy :)
I think you stumbled upon one of the biggest problems of the game, and that is explaining what you need to do. You yourself are actually invulnerable. It is the beacon that takes the damage and it is the beacon that you have to protect. The characters itself cannot take any damage. We really should have told the player aboiut this somehow.
Thank you for yout great feedback. I am happy you enjoyed the game! :D