Every Metroid Prime game ends this way.
A key part to Metroidvanias is that you gain new abilities and then backtrack for things you missed. Retro Studios took it to the next level, hiding several keys to a massive lock on the final boss, with these keys scattered all over the world you’ve been exploring the whole game. They don’t let up with this as we go forward in games, either. I quite enjoy the final hunt: it’s a great way to not feel like I’m accomplishing nothing important while I’m grabbing the last of the upgrades in preparation.
While I do enjoy opening up new areas from my new abilities, I don’t like the backtracking. It’s inevitable, unless you just let the player teleport all over the map, but it’s annoying enough that I rarely feel like getting everything in the game, especially if I don’t know where everything is. I know for a fact that Metroid Prime 3 tells me where things are, so I will be getting 100% in that game, but I’m not too sure about the games before it. There are bonus ending scenes if you find everything, but this is a pretty old game. I’m certain you can find them on YouTube even if they’re not on my channel.