Maybe something like that
not really. if i were to say it it in super basic terms. a circle that goes across a screen, but where it spawns is random in a area, and the player is trying to dodge them.
also I had another idea that like every 3 minutes your alive the asteroids gets faster and you get a pellet that you can shoot at one of them to make the asteroid blow up, but every 5 times that 3 minutes go by it becomes 4 minutes before you get a pellet, so basically every time the timer finishes its run though 5 times the timer adds 1 minute to it and repeats. but i don't know how that would work because the every x seconds would not work.