Having a protagonist who is a master of magic, melee, and marksmanship for free without any effort is silly. What makes any powerful character interesting is when he or she needs to train, learn, practice, make mistakes, try to correct mistakes, etc.
She's being assisted by a minor deity who is powering all her attacks; this is both explained to you in dialogue and is also an actual game mechanic, you have to "mark" enemies by pressing E which causes your deity friend to turn to energy and swarm around the target, rendering them weak to your attacks. After enough blows you get a finishing move which is, again, powered by your deity friend who holds the enemy in place while you deliver the lethal blow. You are not a "master of magic", you have no magic at all, all supernatural abilities are done by the god who is following you around, who is also lending his power to your own physical attacks.
As for the second point, the
entire plot is the protagonist trying to correct the mistake of being directly responsible for the invasion of the zombies. It's so unclear what the fuck anyone's talking about at this point.