Note: All of these games will play on Game Boy Color, original Game Boy Advance, Game Boy Advance SP, and the Game Boy Player accessory for GameCube. None will play on the Game Boy Micro or Nintendo DS/Lite. Only Metroid 2 and Pokemon Pinball are compatible with the original Game Boy (Fat/Light/Pocket/Super).
Metroid 2: Return of Samus (1991)
Amazon:
http://www.amazon.com/gp/offer-listing/B00002SVEM/ref=sr_1_1_olp?ie=UTF8&qid=1270356981&sr=8-1&condition=usedeBay:
http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=metroid+2&_sacat=See-All-CategoriesThis unusual case of a numbered sequel released on a handheld lives up to its title, with numerous improvements and additions over the original NES game. This is the first appearance of elements like the Spider Ball, Spazer Beam, save points, and crouching. Players only familiar with the first and third Metroid games will be surprised to find that this black and white, handheld game clearly bridges that gap and in fact looks and feels much more like Super Metroid. The game structure, however, is unique within the series, as Samus explores deeper and deeper into SR-388 to drive the Metroid species to extinction but finds the creatures have mutated into increasingly dangerous forms.
Pokemon Pinball (1999)
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http://www.amazon.com/gp/offer-listing/B000031KJL/ref=sr_1_1_olp?ie=UTF8&qid=1270357385&sr=8-1&condition=usedeBay:
http://shop.ebay.com/i.html?_nkw=pokemon+pinball&_sacat=0&_trksid=p3286.m270.l1313&_dmpt=Video_Games_Games&_odkw=metroid+2&_osacat=0&bkBtn=Arguably the most successful Pokemon spin-off game, both in sales and quality, this is an excellent and accessible pinball game with one major twist. Playing well offers chances to capture Pokemon and build up your Pokedex, just like in the RPGs. This feature, and all the mechanics supporting it, bring a longevity and depth to Pokemon Pinball that is rarely found in the genre. Note that this black cartridge will run on the original Game Boy (in black and white) or Game Boy Color (in full color). The game has built-in rumble powered by a single battery, but this feature is entirely optional and doesn't work well in the Game Boy Player.
Bionic Commando: Elite Forces (1999)
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http://www.amazon.com/gp/offer-listing/B00004R9HX/ref=sr_1_1_olp?ie=UTF8&s=videogames&qid=1270357866&sr=1-1&condition=usedeBay:
http://shop.ebay.com/i.html?_nkw=bionic+commando+elite+forces&_sacat=0&_trksid=p3286.m270.l1313&_dmpt=Video_Games_Games&_odkw=pokemon+pinball&_osacat=0&bkBtn=This overlooked action-platformer, developed at Nintendo Software Technologies, is more sequel than remake to the classic NES game. The level designs are nearly all new, and the characters (including a new female commando) have new moves. They'll need them, because this GBC exclusive is extremely challenging, just like its predecessors and successors.
Wario Land 3 (2000)
Amazon:
http://www.amazon.com/gp/offer-listing/B00004S99X/ref=sr_1_1_olp?ie=UTF8&s=videogames&qid=1270357931&sr=1-1&condition=usedeBay:
http://shop.ebay.com/i.html?_nkw=wario+land+3&_sacat=0&_trksid=p3286.m270.l1313&_dmpt=Video_Games_Games&_odkw=bionic+commando+elite+forces&_osacat=0&bkBtn=Although the previous game in the series was re-released as a dual-mode cartridge near the GBC launch, Wario Land 3 takes full advantage of the hardware as a GBC-exclusive game. This sprawling platformer features a non-linear world map, multiple level exits, upgradeable abilities, and brilliant puzzles. As in WL2, our anti-hero is immortal -- enemies either knock away coins or transform Wario into a variety of altered states that can be simultaneously annoying, useful, and hilarious. Both in technology and game design, this may well be the most ambitious GBC title from Nintendo before the platform was pushed aside for the Game Boy Advance launch.
Metal Gear Solid, a.k.a. "Ghost Babel" (2000)
Amazon:
http://www.amazon.com/gp/offer-listing/B00004LC81/ref=sr_1_1_olp?ie=UTF8&s=videogames&qid=1270358415&sr=1-1&condition=usedeBay:
http://shop.ebay.com/i.html?_nkw=metal+gear+solid+game+boy&_sacat=0&_trksid=p3286.m270.l1313&_dmpt=Video_Games_Games&_odkw=wario+land+3&_osacat=0&bkBtn=Though sharing a name and some elements from the PlayStation MGS, this handheld game is entirely original and is considered canonical within the Metal Gear franchise. It is played from an overhead, 2D perspective like the original Metal Gear and Metal Gear 2: Solid Snake, but incorporates more modern controls and features from the 3D revival. Famously, MGS for Game Boy spent years as the #1 best-reviewed video game among all platforms at GameRankings.com. It is currently #12 and the highest ranking handheld game on that list.