It's an Open-World Action-RPG which offers a ton of stuff to do, quite a few innovations compared to the last 2 games (different Skill System, base-building gameplay, Raids-Assaults, trillions of new secondary activities and mini-games), and is set in 9th century England (with lots of historical figures of that era appearing, most of which are remarkably accurate historically, if you exclude the obvious Templar-Assassin additions of course). You also have dialogue choices in all main quest chapters, which affect both the final ending you receive as well as secondary aspects like which NPC ends up as the king/jarl of the various kingdoms in the game world.
I get where the "journalists praise it, therefore it must suck" mentality is coming from, and Ubisoft has certainly cucked out it almost every regard (there is even a disclaimer that "this game is made by people of all ethnicities, religions and sexual orientations" at the start of all their games), but as far as Assassin's Creed titles go, this is one of the good ones. If someone had fun with Origins and Odyssey and is looking for something similar and improved, he'll thoroughly enjoy Valhalla. If someone doesn't really care for the general Assassin's Creed gameplay (parkour, stealth, assassinations, exploring the open world, collecting stuff, doing various mini-games etc), then obviously he won't enjoy this one as well. There's not much else to say about it.