Got Platinums #5&6 in the last couple weeks with a couple of really good Metroidvanias: Axiom Verge and Dust: An Elysian Tail. Now my list looks like:
Final Fantasy XIII
Final Fantasy XIII-2
Lightning Returns: Final Fantasy XIII
Back to the Future: The Game
Axiom Verge
Dust: An Elysian Tail
Up next: Dragon Fantasy: The Black Tome of Ice!
If anyone is looking for a great Metroid-like game, I can't recommend Axiom Verge enough. It really was a perfect game for the genre. Had a little bit of so many great classics including Metroid, Castlevania, Bionic Commando, Mega Man, Kid Icarus... just so much fun. Challenge was pretty tame, but acceptable.
Dust was also good, but I played on Tough difficulty (second hardest difficulty) and it was VERY easy. Died a few times, but I don't expect to beat every boss on the first try (which I did). That was disappointing, but the gameplay was really cool.