Zangeki no Reginleiv is a terrible game, but don't hold that against it. Some of my favourite games are terrible, like Sumotori, or Michigan: Report from Hell, or Raw Danger, or Jambo! Safari, or indeed Earth Defence Force 2017, developer Sandlot's previous game. Zangeki - a Japanese-only, Wii-exclusive release - looks like a low-budget arcade game from the late nineties, it has ludicrously awful physics that send dismembered enemies whizzing comically across badly rendered landscapes, its trees look like seaweed on a stick, its cut-scenes stutter and jerk, the main characters spend half their lives caught on scenery and the camera doesn't work. Sometimes, it's enormous fun.
That's not to say that there aren't impressive things about the game. It has hundreds of different weapons, a really satisfying control system (when it works), and brilliant comic violence. You control talking hawks who transform into Norse gods on the battlefield, Frey and Freya, as they fight off a vast onslaught of ogres in order to... actually, I have no idea why. Zangeki does have a story, with cut-scenes and everything, but it's just random Norse gods being imposing at each other. You'll want to head into the options and switch the auto-skip on as soon as possible.
The meat of the game is senseless slaughter and dismemberment of these charmingly badly-animated beasts with a massive variety of weapons. Frey, the male character, can use swords, greatswords, hammers, bows and spears, equipping any two at a time. Freya, the female, is a ranged character who uses much better bows and a bizarre wand thing that spits globules of neon glass at ogres until they explode. A gauge at the bottom of the screen limits her ranged ammunition, and can be refilled by diving in with a sword for a while.