Unfortunately a big disappointment

I can't recommend this game. I guess it's fine to play it just once. After Origins and Odyssey, which were both superb games, I expected much more from AC Valhalla, but sadly I found it to be a downgrade from previous games, in almost every aspect.
Short-story: Valhalla is not so fun compared to its predecessors, and much more forgettable. Also, it borrows too much from the older games.
Below I will leave some hints on what to expect, based on my opinion after completing the game:
- Graphics look good and the viking-theme is interesting, but the setting is not better than Ancient Egypt or Greece; of course this would not be a problem IF all this big map wouldn't look the same
- Following the above, there are a lot of points of interest to complete, which should encourage the player to explore them, however they are just too repetitive and get boring quite quickly. Therefore, I would say that exploration is not rewarded enough, both visually (e.g. nice new places to discover) and as in-game rewards (e.g. new gear); some view points are in the middle of nowhere, far from anything, and seem to be placed randomly
- Another bad/frustrating element about the exploration/looting would be that any chest and other insignificant collectible is made as a puzzle, which is not quite funny after a while
- The game seems just too easy; I understand that it is made for the large public, but higher difficulties just make the game more time-consuming and not harder, at least in my opinion
- I did not enjoy the boring dialogues, repetitive quests and some of the voice acting; characters are easy to forget, I skipped a lot!
- Stealth feels broken: sometimes is works, sometimes it behaves strangely (e.g you can be seen through obstacles, detected from afar, not spotted at all)
- The combat: I'll just say it's for sure worse than in Origins/Odyssey
- Furthermore, the skill tree seems complicated and challenging at first, which would be a good thing for an RPG, but they really don't matter that much and are just small perks; some of the skills are special abilities, still most of them just improve your stats and you won't really notice any difference; I personally didn't like the leveling system (one quest gives you 2 skills points to spend). Last but not least, in the end you get all the skills so the feeling of building your character according to your playstyle is gone
- The game crashes constantly and this seems to be a common problem that has not been solved for quite a long time, despite of many complaints; UBI launcher has problems - constantly not being able to sync, logging out and sending verification emails without a reason
- There are quite a few bugs and glitches, nothing too serious, but together with the crashes and long loading times it can get frustrating
- No achievements on steam; while this is not a big deal for me, I realized that the community complained and I approve that there is no reason why they wouldn't add them
- Weird camera angles and focus sometimes

Now some good things:
- Music is still good, still not at the same level as previous 2 titles
- Horse mechanics seem to be improved, training is a good idea but it needs more elements
- Both male and female main characters are likeable and seem equal this time
- Fps is constant and the game runs well (besides the crashes and long loading times)
- Character customization is fine, I had a lot of in-game currency to purchase what I wanted from the merchant; you can get as free rewards items that you will normally have to pay for, also there are some bonus rewards that you can get with UBI credits and you have a lot of options regarding paid stuff.

Verdict:
I do not recommend it. I can't say that you must avoid it, you may give it a try, I'm sure some will like it, just don't have high expectations like I had. Anyway, I would not pay the full price but wait for a sale.
Please note that I did not try the DLCs and do not plan to get them. My opinion is that their price is too high, just to extend the game that is. Basic version is already big, try it and then get the DLCs (on sale!), if you really liked it.
There is more to be told about the game, but this review is already quite long and I hope it's enough for an opinion. I also hope that I don't seem to be complaining too much but sadly that is my honest opinion.
Good luck and have fun! Comment section is opened for any questions.

After playing the game with no rush I feel like writing a review about it’s duty. First of all, I expected much more from it. It’s not that bad but I think it is one of the most over rated games ever. If you are looking for a hard, real RPG, you are not going to like it. They said it’s inspired from Gothic, but it’s more like newer Assassin Creed games. The game had huge potential, but in vain. They could take much more from older similar games and just implement/improve it.
Some points that I would like to highlight, just to make it easier for you to know what to expect:

The BAD:
• MOST IMPORTANT: this level thing for enemies must be removed forever from games like this...it really destroys the feeling you should get for the time spent to develop your character. You know what I mean - let a wolf be a wolf and a dragon be a dragon. Not a level 30 wolf to 1-hit you and a level 5 dragon not to touch you
• Game is too easy – even on hardest difficulty, everything seems overpowered, doesn't really matter what skills you learn, what approach you choose, what gear you go for
• Combat is bad/cluncky – you can just spam dodge forever, you can eat in-combat, you can pause the game in-combat to repair your gear, apply oils, etc and you have Quen that is also spammable; all these make the combat and game in general way too easy and not challenging
• It really gets boring at times
• Plants and monsters respawn over and over again – so most of the resources are just a matter of time, you don’t have to be cautious how you spend them
• No animations when you pick up plants, loot chests, packages and more, infinite bolts from your crossbow – in a medieval RPG like this? No thanks. (and many more things like this that will crush your expectations)
• Absolutely ridiculous fall damage combined with pretty long loading times makes it really frustrating
• A minimap that acts like a radar – you can see enemies/monsters/plants on it before you actually spot them; only casuals would want it in a game like this
• XP is not balanced for main/secondary quests/killing monsters; you only get some real xp from main quests and a few secondary quests linked to the main; almost 0 xp for killing monsters and other small quests
• The way skills are designed is awful for most of them. You don’t get new animations, just + percent/points for something. Lots of them are overpowered but in the end it does not really matter because skills are just small perks and it’s not important how you build your character
• Exploring is not rewarded enough (about both looting and discovering new places) - the big map feels empty, almost everything is marked on map with a question mark, places are repetitive
• You can’t run from a fight as you should be able to, your character stops from running and faces the enemy. Fist fights and horse races are an embarrassment.
• Game is just not interactive enough: i.e you can talk only to NPCs that are involved in quests, or to merchants. Even if you save a prisoner, after freeing him it does not interact with you.
• Some other little bugs and glitches that could be ignored but this situation just rise the frustration level. (horse gets stuck, dialogues not showing, can't get out of water while swimming near shore, and many more!)

THE GOOD:
• Graphics are nice and there are some beautiful sights
• Medieval nice atmosphere overall
• Music is ok but could be better
• Many rpg elements – unfortunately not so impactful
• Variety of monsters with their weaknesses
• Variety of items and skills (again, they don’t matter that much)
• Nice inventory – many don’t like it but I find it pretty convenient (bonus: horse items)
• Gwent – a very nice minigame that I enjoyed
• Pretty well optimised

Verdict? Way below my expectations. You may buy this game on sale, there is a good chance you will like it if you are a casual. If you want a real RPG like Gothic, Risen, you will find it boring. Don’t pay full price regardless, buy it on sale!

Are the expansions worth it? Compared to the main game - yes! There is a lot of new content: missions, places, items, characters, etc. But I strongly recommend to buy them on sale also.

For debates/questions I leave the comment section opened.

Last edit: This review has been adjusted after playing 135 hours, in which not only that I finished the main story, Blood and Wine and Hearts of Stone DLCs, but explored and tried almost everything this game has to offer.