Ratchet and Clank series

Aquaria, on PC, the only difference is that you swim instead of jump :P

Outland. It just came out last week, and fits the genre well (with a splattering of bullet hell thrown in).

That game looks really interesting.  And it definitely looks like it fits.  Some of the game engine and areas even look inspired by Symphony of the Night.

I can't really tell entirely what kind of gameplay Outland is.  Watching it, it seems to have the staples of a 2D Platformer, but I don't know about free roaming and item progression.  It looks like you just obtain items from getting more coins like say WarioLand Shake It.

I'll put it in thr cross genre section unless you've confirmed it has those other two aspects.

You consider Assassings Creed and Infamous as action platformers??? thats interesting i always consdiered those as open world games. there arent really any stages in AC, just a bunch of missions you do until you unlock more of the world. Not that much different from GTA. Infamous IMHO has more in common with Spider-man 2 than Metroid.  We're getting a new AC this year, Infamous 2 is around the corner and Arkham City is not far away, seems like you have an issue with the 2d ones not coming and yeah that kind of is a problem

The first one is very much a Metroid style game with straight item progression (new item each completed mission) and rewards for exploring outside the main story areas.  But yeah, I will admit the sequels have a lot more going on and can be considered anything from Quazi-Sandbox games to freeroaming Adventure games.  But since they still build off the item progression/exploration factor of the original.

Assassin Creed II actually improved the reasons for exploring off the main story path by unlocking additional aspects of the story and getting a few extra weapons.

^^^ Assassin's Creed 2 wiped 1 with its ass, much better game. I stopped playing 1 early on, cause i got frustrated, but i could see how the original can be compared with Metroid. IMHO AS 2 & Brotherhood, as sandbox games beat even GTA's ass. 

Agree about Princess Crown. I listed it because of  Odin Sphere and Muramasa being on list.  btw I think Trine (PC, PSN) would fit this category.

Phantom 2040 for the Super Nintendo, Sega Genesis and Sega Game Gear.

It's like five bucks on eBay. Check it out.

I just talked about this very game a few hours ago in another thread. I feel like a promotional whore.

What about Oddworld? the 2D ones I mean, Oddysee and Exodus. If you count these then you might count Flashback also.

Else I can only think of Blaze & Blade: Eternal Quest for the PSX.