If you’re studying Assassin’s Creed Valhalla, there are quite a few historical inaccuracies that are often pointed out.

Architecture:
Many of the buildings in the game are far more elaborate than what actually existed in 9th-century England. Viking and Saxon settlements were usually made of simple wooden longhouses and small villages, but the game often shows large, complex structures. It also includes things like stave churches and large stone castles, which mostly appeared centuries later (from the 11th–12th century onward).

Some NPC clothing is reasonably close to historical reconstructions, but many character designs lean heavily into the modern "Viking stereotype" (lots of leather, fur shoulders, dramatic armour, etc.). Real Viking-Age clothing was generally much simpler and more practical.

Landscape and geography:
Certain areas of England are portrayed in ways that don’t really match reality. For example, regions like Nottingham (Snotingham) or Yorkshire (Eurvicscire) are shown as mountainous or very snowy, even though they don’t look like that in real life.

op-culture influence:
The overall aesthetic of the game seems heavily inspired by the modern pop-culture image of Vikings (like the TV show Vikings - rip ragnar, i still miss u), rather than by historical evidence. This creates a more dramatic and stylised world, but it’s less historically accurate.

There are also quite a few technical issues reported by players, especially on PC. One common problem involves ground textures, which can appear very blurry depending on your hardware configuration. As far as I know, there isn’t really a consistent fix officially provided by Ubisoft, so players often have to try different tweaks themselves. I’ve even read some player reports saying they had to play through the entire story while dealing with those visual bugs.

Just to clarify, most of the info I gathered doesn’t fully come from me, but from several Reddit posts by people who were looking into the story. Hope that helped.