All Game Boy games were compatible. Which weren't? The only one's that weren't compatible were much later, Game Boy Color games (even though some GBC games were still compatible with SGB).

There were lots of Game Boy games made especially with the Super Game Boy in mind.

Just think of all the Super Game Boy fighting games (Street Fighter II, Battle Arena Toshinden, Killer Instinct, World Heroes 2 Jet, The King of Fighters '95, Samurai Showdown, etc.), you could play with two SNES controllers on one TV screen.
If you played them on Game Boy, you needed two Game Boys, two of the same game, and a Link Cable.

What about Super Game Boy games Donkey Kong Land 1, 2 ,3. Their pre-rendered style wasn't a good fit on the classic old screen.
The details (especially the blurryness on the fast scrolling) were easier on the eye - a non-issue - on the Super Game Boy.

I always prefered Super Game Boy over the old Game Boy. The Game Boy can only show 4 colors and run in mono, but the Super Game Boy added extra features like in Donkey Kong and Animaniacs that had up to 16 colors (maybe more?) on a single screen, and stereo sound that could also play voice samples or an enhanced soundtrack. (Many games suddenly looked and sounded better than NES games.)
And the curiosity that is the Super Game Boy game Space Invaders, that can switch to an exclusive, full screen SNES mode.

Other than that my most memorable Game Boy moments were dedicated Super Game Boy games running on the Super Game Boy: Kirby's Dreamland 2, Adventures of Lolo, Mario's Picross, Kirby's Block Ball, Pokémon, Tetris Attack, Dragon Warrior Monsters, Wario Blast, Harvest Moon, Game Boy Gallery, etc., http://en.wikipedia.org/wiki/List_of_Super_Game_Boy_games , etc.

The reason I am worried about TG16 games not returning for the Wii U VC is because they were announced to come to the 3DS VC as well but never showed up. It's probably been two years since that announcement. Also, NA never got Adventure Island II for NES after Europe did. But, I am hopeful that with the excitement surrounding the launch of the Wii U's VC that Konami will see fit to release TG16 games again. And hopefully improve the blurry emulation as well. What was up with that?

...Wait so how does this upgrade thing work again? Because I kinda find the whole thing kinda pointless...like, I can already play them on the Wii U via Wii mode...lol

I stopped reading this thread about 5 pages in, but I'm throwing in my two cents because I'm surprised at how many people are actually cool with this decision by Nintendo.

The fact of the matter is, whether you care about Virtual Console or not, Nintendo started a service and they should support and handle it more responsibly than this. I, among hundreds of other people, have invested a ton of money into the VC service, trusting that we'll be taken care of in the years and generations to come. When Nintendo announced that Virtual Console titles would be transferable to the Wii U I was jumping for joy, so much so, that it solidified my decision to pre-order the console as soon as possible. I used my Wii for Virtual Console games more than anything else, so naturally I was hoping for the service to migrate over to the new console.

I was disappointed however, when I discovered that the games relied on the use of Wii Mode, and weren't integrated in any way with the new interface. I couldn't use the Friend List, access Miiverse, or even check the damn time like you can with the Wii U Home Menu. It's small things, but it's those that count for more than you'd think. So in finding out about Nintendo's plans for this new "Wii U Virtual Console" service, it should come as no surprised that I'm actually pretty shocked, and kind of upset. I don't know what to be more upset about, the fact that they are practically restarting the entire service by slowly releasing games over the next few years, (which was painful enough waiting for over the past 6 years) or that they aren't allowing you to simply carry over your existing catalog to be used with the new Virtual Console. (Which let's face it, is just another emulator, not an actual re-coding of the game ROM)

It's moves like this that make me wonder if Nintendo even really cares about the "consumer", because all I see is a loophole for them to make more money. I thought Virtual Console was the iTunes or Steam of classic video games, a service which would always be there, yet evolving with the times. I guess I was wrong about it. I see a lot of people saying "if you don't like it, don't upgrade your games then." which sounds like a really passive way of dealing with it, but I think I'll do just that, not support this decision from Nintendo. At this point, I regret investing into the Virtual Console service in the first place, and this whole thing even makes me wonder about downloadable services in general...

Maybe from now on I'll stick with collecting original copies of games.

I was talking about Super Gameboy enhanced games. Though there's no way to emulate the Super Gameboy.

@Neram
Paying an extra dollar or two to add features is nothing new to video games. All we are seeing is Downloadable Content being released for Wii VC games. This new DLC will add functions such as, GamePad only support, Miiverse, and Save States. I even remember hearing talk about adding online multiplayer to some titles. All of this does cost Nintendo a lot of money to implement into each game. If you don't want to upgrade your game then don't pay for the extra DLC and continue to enjoy your full game.

Taking my Japanese Wii into account I have also spent a lot of money on the Virtual Console, but I certainly wouldn't have expected the level of support you're talking about - that's like expecting Nintendo to warrant your NES carts today which is ridiculous. Your comparison to iTunes does iTunes too much credit as well as content occasionally gets removed, meaning you cannot be guaranteed a re-download of music or movies you've purchased (and I buy a lot there too).

The fact is we're entering an age of ephemeral media, but then nothing in our culture is forever, not even the physical media. If it makes you feel better to think that a century from now your old game console will still work, then go ahead and collect carts, but none of it will last. Myself I'm just enjoying this stuff whilst my mind and body work well enough to play - an extra .99 for some of it (I only expect a fraction of my VC collection to appear on Wii U - no doubt new games will get the focus - as they should) is nothing to me, though like you I had expected a neater solution than "Wii mode." That's not to say that couldn't change though, it is early days in the system's life!

And you can by keeping them on your Wii and playing them on your Wii like they were meant to be. Honestly I sunk a ton of money into my NES and SNES collection Nintendo should have made an adapter so that I could have play my NES games on my SNES and an adapter for the N64 so I could play my SNES. Heck they should have given me an adapter so I can my NES games on every Nintendo system that comes out hence forth. You can see where I am going with this.

Honestly I dont understand why people think that their are entitled to be able to play games from a past console on a current console? Your lucky Nintendo is even offering this service. If you ask me you are all acting liked spoiled brats.