I'll be upfront -- I've barely played any iteration of Metroid. This probably has something to do with me being almost exclusively a PC gamer, one who's more interested in making games than playing them. So this video, which I'm assuming accurately condenses the Metroid series into an animated, fast-spoken minute, was something I found incredibly informative.
Even when I've played the odd 2D platformer, I can't say I paid much attention to their back stories, but after watching the clip, I find myself intrigued by whatever Nintendo concocted for Metroid. I realise the series made its way into the world of first-person shooters once it got off the retro consoles, but I can remember my brother playing the heck out of the original many, many years ago and for me, that's how I'll always picture it.
That, and the incoming nightmares of creepy bird men standing over me on an operating table.