The DestroyByContact and Game Controller codes from the tutorial don’t work. The asteroid doesn’t get destroyed and the Game controller doesn’t spawn any asteroids. I switched to the “Done” scripts to see what it’s supposed to be like. They don’t work either.
It looks like you are forgetting to set the Game Objects “Player” and “Game Controller” tags in the corresponding Game Objects.
Check this link if you don’t know hot to tag a Game Object.