Quote Originally Posted by hroşila View Post
As others have noted, it can mean an ordeal in general, but in this context I'd say it's specifically the gaming term which refers to a challenge where you must beat a series of discrete levels in a single run.
See this.

According to Wikipedia.
Guantlet the glove is from French.
Guantlet the ordeal is from Swedish, but the English pronounciation and spelling came to match the glove since that was a familiar term in English.