Even back in 1986 Nintendo was opening up Metroid for a sequel. It's also kind of strange/fun to see a Nintendo game talk about praying for peace. Who does Samus pray to for peace and what is her belief system? I tried to do some searching to find out and it seems the Metroid Wiki doesn't seem to know either because talking about the Galactic Federation in the Metroidverse they say:
"The specifics of culture, religion, trade, currency, technology, civil rights/liberties, and so on are also unknown."
It's also like how Nintendo put a cross on Link's shield in the original Legend of Zelda but Link isn't a Christian. I think old school Nintendo just picked these words and icons without thinking too much about lore because they were easy to understand and are now a fun discussion point.
But I digress because the point of all this is to say I FINALLY COMPLETED THE ORIGINAL METROID. Which was a fun tick on my video game bucket list. As I said before in talking about playing NES Metroid, the game really opens up after you collect 3+ Energy Tanks and the Varia suit and also improve in the way of the games platforming. So if you have a NES Classic, the ability to get a map of the game and some time, I recommend you play the game if you haven't yet.
I'm planning on playing Super Metroid when I open my SNES Classic and then after that want to tackle the 3DS Metroid Samus Returns. I've considered coming back to Metroid II on Gameboy but decided against it and are going to come in the 3DS game fresh.