Force them to jump in the tutorial, and solve the main boss thing through normal storytelling, whichever way makes sense for your game. If the only time you need to know something is late game and there’s nothing to remind you mid-game, that’s poor design.
On the other hand if you don’t make people read, you end up with “Who the hell is John MainBoss?” or “This game sucks, how do I jump?”
Force them to jump in the tutorial, and solve the main boss thing through normal storytelling, whichever way makes sense for your game. If the only time you need to know something is late game and there’s nothing to remind you mid-game, that’s poor design.