Achievements / Missable
Is anything missable?
One thing is. Every collectible can be picked up after the credits through chapter select, so the instinct to sweep every room before a door shuts costs you hours and buys nothing. Resonance Points are the exception, and they are the only reason to pay attention on the way through.

The one missable
Resonance Points do not carry over in chapter select. They are the game’s skill points, and buying every skill in all six mastery branches costs 15 + 20 + 25 + 30 + 35 + 40 = 165 of the 200 in the game. That total has to be found inside one playthrough, which makes Like a warrior the only achievement here you can lock yourself out of.
They also bank at checkpoints rather than on pickup — die before you reach one and the points you just collected are back in the world. You have 35 spare across the whole game, so it is forgiving, but it is not free.
What that changes about a first run
Play the story, but pick up the lights
Combing corners for chests is wasted effort — you can do that later. The glimmering white lights are the ones worth stopping for, because those are the points that do not come back.
There is no New Game Plus
Chapter replay is the mechanism, not a full second run. So the clean-up pass is targeted rather than another playthrough.
Difficulty is not a lock
The options go far enough down that damage stops being a constraint, and nothing in the achievement list is gated behind a higher setting. Lowering it does not cost you points either.
What you will be collecting
Artifacts
Small collectible objects that carry a piece of backstory.
Resonance points
Found in the same hidden corners, tied to the game's central motif.
Charms
Come out of chests rather than lying in the open.
So why does almost nobody finish?
If the only missable is one you can plan around, the difficulty can be turned down and the clean-up is guided, then 6.2% of owners holding the finish-every-chapter achievement is not a story about difficulty. It is a story about people stopping. The funnel shows where they stop, and it is earlier than you would guess.