Owlboy

You need to collect all the coins in all locations. Can be tracked through game statistics.
If you missed something, I advise you to first reach almost the very end/point of no return and start cleaning up all the locations. For example, you can return to the cave right away, but there will be a blockage that prevents you from passing, but at the very end this blockage will disappear. I advise you to immediately play carefully, lick all the walls and kill all enemies (with the exception of stealth missions).
Coins are hidden:
In chests
In objects pulled out of the ground (inedible)
For flying through the rings
Behind illusory walls
For killing all enemies in a certain location (a chest appears).