first- thank you very much for your comment, this really motivates us! There are few kinds of asteroids, they are just moving fast so you cant really notice but they have different score and damage. Also, on the bottom of the screen there is an HP bar! Each asteroid that touches the floor gives you damage. And there is also an HP bar to the space ship. That is the goal - killing it with your sword. Just a spoiler- if you didn't noticed, your sword gets longer (long sword...) as you progress the game. And when its long enough you can defeat the space ship.