Need a good 2D game

Im looking for a good 2d game, some kind of platformer, or an overhead shooter. I know some of you guys remember 2D, and if not, go look at a gameboy advance, you'll see what I mean.

Im looking for something along the lines of Contra, or R-Type. Any suggestions? Any that will run in XP? Any that don't look like they were made in 1982?

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