Why works safedisk 2 game in cd burners

I made a copy of a game called mulle meck ( swedish) and the game works perfect in my cd burner (plextor 8432 firm 1.07) but not in a cd reader. The game is protected with safedisk 2 ,bad sector and it´s overburn.Anyone know why the game works in my cd burner and not in my cdreader. It was the same with stcc 2 and Alice in wonder land ????

Anyone know why