Now the problems in your code:
-The mummy was following X=0. The player is on the center of the screen so I changed it to X+200.
-Try to not use goto. I know that in the examples they use that but it make the code confusing and hard to read. Only use it inside a function(Becuase the goto can only jump to a line inside of it).
-Declare the variables that you're going to use(Use VAR or DIM)
2そうだね プレイ済み