The sea rises regardless
The one non-negotiable rule of the game, and — it turns out — of the life. Do not soften it.
The rule
In Saltwater Almanac you play Wren, keeping a lighthouse on a coast that is going under. You can do everything right. You can catalogue every tide-pool, log every storm, help every last villager pack the car. The sea rises regardless. There is no ending where you save the shore, because there is no such ending available to anyone, and a game that pretended otherwise would be lying to me in the exact place I most need it to tell the truth. See Design Pillars and the long argument in The Ending Problem.
Agency moves from the world to the witness
The obvious objection: if the outcome is fixed, why play? Because the outcome was never the site of your freedom. What you cannot change is that the sea rises. What is entirely, achingly free is what you notice on the way down, and what you carry out. Agency does not disappear; it relocates — from the world to the witness. You cannot save the coast. You can save the record of the coast, which is a different and a realer verb.
Why it is a life philosophy, not a downer
Because it is simply true, and pretending otherwise costs more. Everyone I love is standing on a coast that is going under, myself included. The rising is fixed. The attention is free. That is not despair — despair is what arrives when you have decided the only meaningful act was stopping the tide. Put the meaning where it actually lives: in the noticing, in the carrying, in the quality of attention you pay to a thing precisely because you cannot keep it.
The sea rises regardless. Keep the almanac anyway. Especially anyway.