What are you playing? c'mon, tell me punk!

[Zero Kirby]

The only problem I had with Metroid Prime 2 was the Boost Guardian. Hardest boss in the game, I think. I don't know how I beat it when I played again on hard mode. I've never played the Trilogy version, only the GameCube.

Oh, and about those temple keys - I never had a problem with them! But I'll admit that I was lucky that I figured out they were all in the opposite world versions of the rooms with the dead Luminoths once I grabbed the second one.

I failed to make that connection :/
Then again, I couldn't be bothered to remember where all the bodies are.

If you had scanned the bodies, they all have unique Luminoth Lore that hints to where the keys are.

And I believe at the actual door to the Sky Temple, each of the key slots can be scanned to give you hints to where all the bodies are as well.

Either way, all the information is actually in the game.