1) Meta Ridley
Featured In: Metroid Prime (2001)
At the very beginning of the game you are sent to infiltrate a Space Pirate research facility orbiting the planet Tallon IV, and after defeating the Parasite Queen the facility begins a self-destruction countdown. As you make your way out, you come across a well-known face: Ridley, only this time he's been completely outfitted with a cybernetic body (a la Darth Vader) after you defeated him in Metroid/Zero Mission. Meta Ridley escapes and flies towards the planet, where you lose him and begin investigating Tallon IV.
The fight with Meta Ridley plays out in two phases. At the beginning, he flies around the platform that you're stuck on, occasionally bombarding you with his kinetic breath weapon and seeker missiles. From time to time he will fly up in front of you for a close attack; this is your prime (ha!) opportunity to blast his weak point, his chest plate. Once you've knocked his health to about a quarter, his wings burns off and phase two begins.
Ridley is far more dangerous once he's been grounded. For starters, the platform you are on is quite small, forcing you to stay close to him. He will charge Samus, hop a few times creating shockwaves, or swipe you with his tail. He tends to stay on all fours, guarding his chest plate more fiercely than before.
Nevertheless, Samus comes out on top and Ridley's suit overloads, causing him tremendous pain. The Chozo statues then come to life, and proceed to blast him off the platform. Samus looks over the edge to see her fallen foe, but we know this isn't the last time we've seen the persistent Space Pirate commander.
And it isn't. Next time you see Meta Ridley, you fight him completely in freefall (Gandalf vs. Balrog style!).
The music for this fight is intense and epic, the atmosphere is stormy and really sets the mood, and you're forced to stay on your toes so as to not get caught off guard. Plus, it's Ridley! Whether cyborg or not, he remains one of my favorite video game villains of all time.
1) Ridley (Super Metroid)
Ridley has always been my favorite boss. He looks really awesome, and he's the hardest villain in the game. Plus who doesn't like fighting a huge fire breathing dragon that stabs you with his tail? Everything about this fight is what I love about the Metroid series. And that's why he's my number 1.