GameMaker - Asteroids Part A

https://drive.google.com/file/d/1i_AK6Bj2TkLptRoS2O5DvFmq6FOUeYfj/view?usp=sharing

What difficulties did you have? Hoe did you solve them?
I don't really have difficulties for this part because I was making this game really carefully to not make any mistake.