Cited from Wikipedia

Super Mario Advance 4, excluding the European version of the game, is compatible with the Nintendo e-Reader, allowing players to scan certain e-Cards into the device utilizing two Game Boy Advances, the e-Reader, and a copy of Super Mario Advance 4. Once a card is scanned, it adds certain content to the game. One of the most prominent features included is the ability to add stages to the game; the player is allowed to have 32 extra stages on one copy of the game.

Cited from The Nintendo Wiki

Level Cards will give the player new levels that weren't present in any version of the game. They can only be accessed by swiping an e-Reader card. The Game Pack can hold a total of thirty two stages. In order to add more levels, you'll have to go to a special Level Scan Portal on the game's map that is glowing. After you're there, you'll have to press the A button to start the process. After that a Lakitu will appear at the top right of the stage and an screen will pop up telling you to swipe the card. Once you've done so, you'll shortly be able to play the stage you've just scanned. The only way to save the level to the game's memory is to beat it.

So now that you know about these levels, you might be happy to know that they can be played using the RGR Plugin. I've uploaded 2 save files which have a total of 37 e-Levels to play.

This save file will give you access to 32 new levels for Super Mario Bros 3:
https://www.vizzed.com/boards/upload/files/Super_Mario_Advance_4_Mushroom_and_Promo_Save.zip

This save file will give you access to 5 remade levels from the first Super Mario Bros:
https://www.vizzed.com/boards/upload/files/Super_Mario_Advance_4_Star_Save.zip

After you've loaded this game from the page, close the game window and extract the downloaded save file. The extracted file for both of those downloads will have the same name: Super Mario Advance 4 - Super Mario Bros. 3 (USA), you'll have to move that file into your RGR Plugin Data folder. The save file must have that exact name in order to work.

Note that if you already have saved data for this game, placing one of these save files in your Plugin Data folder will overwrite the existing file and your data will be lost. To avoid losing your save file, you can move your existing file (which will have the same name as the downloaded file) to a different location on your computer before moving one of the downloaded files to the folder. To access your existing save file, move the file back. Or you can save the state with F2 before placing the downloaded file in the folder, as save states won't be overwritten.

Here's the location of the folder on your computer to place the file in, (User-53134 is my user folder) replace '53134' with your user id:

Windows 8, 7, Vista - C:ProgramDataVizzedVizzedRgrPluginUser-53134VBASaves

Windows XP - C:Documents and SettingsAll UsersApplication DataVizzedVizzedRgrPluginUser-53134VBASaves

Or go to:

Start Menu > All Programs > Vizzed Retro Game Room > Open Plugin Data Folder > User-53134 > VBA > Saves

Another great thing you are doing for us here on vizzed.  Thanks for all the games you keep adding even when I think there are none left to add. Good work.  BTW you must be some kind of tech genius.

That's possible!? Wow, somethings you post here I never imagined to be possible that's so awesome.

I'm gonna do this sometime, as I actually beated the game a while back I believe. Thanks

Hey, what about regular E-reader games? Think you could upload those? Here is an E-reader site:
http://ereader.vze.com/

Anyways, nice job! Can't wait to play these!

fightorace : I'll probably never run out of games to add, right now I have about 20-30 new hacks in a folder which I have yet to upload. Also, I wouldn't consider myself a tech genius, thanks though.

imamonster : Thanks for your feedback.

RetroGameNinja : It is possible for other e-Reader games to be available. Most of the e-Reader games are available as save files which can be loaded into either the e-Reader ROM or the ROM for the game which the e-files are for. I planning on looking into how to go about adding more of the e-Reader games when I have free time.

Everybody here, I all wanted to let you know this was my idea to add this add on content.