Aw, most of my favorites were already mentioned. Oh, well, I'm supposed to say what I thought had good art. I was gonna write more in this post, but I spent lots of time capturing screens from Kirby's Adventure which I thought looked neat. I will mention more of my favorites another time.
Kirby's AdventureImpressive artwork (and technically impressive for the NES), full of colorful backdrops and cute animations of a pink puff. Level 3 (Butter Building) had some interesting rotating tower scrolling. Level 4 (Grape Garden) had awesome cloud areas and airships! And Level 6 and 7 had the most varied and awesome backdrops of all, I think (including a large boat in the sunset, a a funky Gameboy homage to Kirby's Dreamland). Not to mention the world map backgrounds for each level were really funky. It even had multiple colorful minigames!
Metal Slug 3These screens are jpeg'd and for that I apologize, but I wanted to pull up some screens quickly. So I just did a google search instead of digging up an emulator.
Well, pretty much any of the earlier Metal Slugs have great animation and artwork. I chose MS3 because it also has some really cool gameplay elements, like zombies (with the ability to vomit blood)!
The first level boss is pretty awesome, too. Click the image see it in action (Looks way cooler than that shoddy capture)
Oh, and to me, the Guilty Gear X games look pretty good, at least in action, on an actual TV screen. Although, they don't look nearly as good as still captures (especially on a computer screen), and I understand not everyone likes weird exaggerated anime-style characters. I think it's the animation style (and the weirdness of the characters) that makes the game impressive to me. It's not really a feat of pixel art, so much as animation. Also <3 Millia Rage.
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