It says another achievement (open game). What does it mean? And how can I get it?

How can I win the boss of this gym? I have no clue how to defeat the final boss. 最后一关的魔男怎么打呀？

^ Title

Upon launching the game, I get a popup screen saying "The UE4-DDF Game has crashed and will close." and the description being "Fatal error."

Did anyone get that achievement? Ive finished the game but still dont have it