Assassin's Creed Valhalla

• The only missables I'm aware of in the entire game are opening a door from the inside of a crypt when the story sends you there (unclear if you can get back there otherwise, there's an item inside), and two "Wealth" collectibles later in an area that feels very much like when you leave you're done, so when you are sent to a crypt or an area the game signposts the shit out of being one-and-done, grab stuff

• You can go back and forth between world-maps (between tutorial area and the main game region) at any time once you unlock the latter

• Respecs are free and infinite, and can be done on either a single-dot or full-tree basis. Once you put enough points into a direction to unlock the next area / clear its fog of war, if you respec you'll retain that vision until you leave the menu entirely. So once you get 20, 30 points under your belt, feel free to mess around and branch out and see what you can build towards.

• Broadly in the skill tree yellow = stealth, blue = ranged, red = melee/combat, but in practice, blue has a lot of QoL stuff (time slow on dodge/low health) and yellow has a smattering of ranged things (notably, steer-arrow-in-first-person).

• When a dot on your compass starts to wiggle/pulse, doing your Odin Sight (the pulse reveal thing) will change the icon to what it actually is, so you can tell if that yellow dot is a resource or an equippable item.