(I'm playing Valhalla on an Xbox One X)
Valhalla is a must play if you're a fan of the old or the new Assassin's Creed games. It brings back the new style of gameplay brought about in Origins and Odyssey (different styles and types of gear, climb almost any surface, mount summoning, bird-companion, conver choices, etc) but it mixes in a healthy dose of what I loved about the first few games such as post-assassination conversations with the target, blending in, and even actual members of the brotherhood (still called The Hidden Ones at this point) to train you. The graphics are beautiful and the world is massive and full of adventure and opportunity. There are no ship battles like those experienced in most of the games since 3, but you can raid villages from your longboat for supplies. Also, you can upgrade your own town, similar to fixing up Monterrigioni in 2. The bows from Origins also make a return, giving you options for archery attacks. Oh and if you thought fire was fun in the 2 previous games, just wait till you burn down a raided village. Or two.
Oh, and yes, you can pet the cats.