I didn't watch the game, but I saw her rendition several times today. Awful!
I'm less concerned about the mangled words than the style. Virtually all pop singers feel the need to "sing" the anthem in a way to feature themselves more than to honor the nation, the nation's history, the flag, the military services and those who have suffered or died for all of us. Universally, they seem to feel the anthem has too few notes, so they put a lot of extra ones in. But the worst is the inability to fight the urge to drawl and slur the words to non-understandability.
Personally, I'd rather not hear the anthem than hear it degraded in that way.