The use of the word "exclusive" has developed into an interesting discussion of semantics this generation. Lately it's got me reflecting on older games. So, for those unfamiliar with Pokemon Gold and Silver...

It says Game Boy Color on the box, as well as on the Japanese cartridges:

There's no question they are Game Boy Color games, as they do in fact support the "color" feature of the Game Boy Color. However, this same cartridge could be plugged into an original Game Boy (released in 1989, almost 10 years before the Game Boy Color) and be played just fine, albeit without color. This is a somewhat unique situation that applied only to a few Game Boy Color games. Imagine inserting Bloodborne into a PS3 and playing a slightly downgraded version of the game. To my knowledge, this hasn't been done before on other systems, so it presents an interesting question.

There are Game Boy Color exclusives like Pokemon Crystal that could not be played on other Game Boy hardware iterations available at the time. So are Pokemon Gold and Silver, released in 1999 and marketed as Game Boy Color games, considered exclusive to that platform, even though other Game Boy models capable of playing the games had been on shelves for over a decade?

The Gameboy and Gameboy Color thing has always gotten me thinking as well. For instance, the original Gameboy did NOT sell over 100 million units but for some reason, it's officially listed as such because everyone lumps the Pocket and Color Gameboy into the same line. It doesn't make any sense.

I would say that if a game was backwards compatible with the original Gameboy, then it wasn't exclusive to anything but Nintendo. It was a "Nintendo" exclusive.

Yeah, I believe one of the Wario Land games was also a Game Boy/Game Boy Color hybrid.

It's definitely a weird specimen that I have no idea how to really explain and describe.

Pokemon Yellow seems to have a decent amount of color support compared to other original Game Boy games, such as Pikachu being in full color in the intro and title screen, but it was still packaged as an original Game Boy game.

There were also games like Hamtaro Ham Hams Unite, and Shantae, which got a few bonuses and minor tweeks when played on a GBA, but again, those were still just Game Boy Color games.

I guess in more modern times, the closest parallel I can think of is Hyrule Warriors Legends, where the game was clearly meant to be played on a N3DS, but can still be played on an standard 3DS, albeit with horrendous framerate.

Good comparison, although HW Legends isn't sold in a "*NEW* 3DS" box like Xenoblade 3D was. It's not marketed as a New 3DS game.

Does marketing play a role in the technical exclusivity of a game? Much is made of the advertising arrangements for Destiny and Battlefront on PS4. Sometimes such games are treated like Sony exclusives, even though they are also released on other platforms. So does this argument apply to a first-party trying to phase out older hardware?

Come on now, that's cheating. This is a yes or no question.

I used to play Pokemon Silver on Gameboy Pocket when i was 10 years old lol

Whoa that Pokemon gold cart looks really cool namely because the Pokemon and not just the title is on it. Wish they did that for all the Pokemon games!

Come on, that's cheating. Besides, GBA hadn't even launched yet when Gold & Silver were released. Am I to understand that any exclusive game loses its exclusivity upon the launch of a backwards-compatible successor?

Next you will tell me DSi shouldnt count as the DS family of systems and New 3DS isnt apart of the 3DS family

GameBoy Color is just another member of the GameBoy family and sales should be counted as such. 

Why is this an issue, like Pokemon Black and White it has exclusive features on the newer iteration of the handheld but is still playable on the older versions

It's not an issue. Just a curiosity.

Well, as far as this example is concerned this is not an issue.