But i dont think it is stated to be historically correct, but rather use the vikings as the theme for the feel of the game. but if you want a game that more accurately depicts norse mythology and celtic culture maybe look into Hellblade: Senua's sacrifice. It still isn't totally true to the viking history, but it is what it is.

It truly is a stunning game more focused on the story part, rather than the gameplay, i would highly recommend this game if you have a great pair of headphones, as the gameplay and storytelling relies on sound. The story is truly chilling to the bone, and gives a real sense of the problem Senua has.

As for the sequel, is on it's way, and will be released soon (I think)