Valkyries are a joke when using Zeus armour

Even on the hardest difficulty, if using the Zeus armour you can utterly demolish the first eight Valkyries before they've even had a chance to fight back. 3 minute video

Edit: For those wondering, the Zeus armour set can only be unlocked in New Game Plus, by defeating the Valkyries. To unlock and fully upgrade it you pretty much need to complete the game twice. You will need to start a third run to use the set from the start.