Super Mario Special 3 is indeed a bootleg game. According to Bootleg Games Wiki, the game was made in 2000 by bootleg developer Yong Yong who also made other GBC ports of popular games, like Sonic 3D Blast 5 for example, which is a badly designed Sonic port, and they still make games for mobile devices these days under their new name 'Makon Mobile Studios'. It's essentially a buggy port of Super Mario Bros. 3 to the Gameboy Color. Supposedly the company released this game in both a traditional GBC cart casing but also in a GBC rumble cart casing, and Yong Yong is known for doing this with some of thier games. It seems pretty awesome at first, but it has a few fatal flaws.
-HIGH-PITCHED NOTE THAT NEVER ENDS: Eh, the most noteworthy flaw is the high pitched note that never stops playing. Yeah, instead of music or sound effects you get ear-raped by this high pitched note. Best to play this game with the sound off.
-PHYSICS AND MOVEMENT: Also noteworthy is the fact that the physics are screwed up. One example of this is when you stop after Mario moves. You'd think Mario would move slow then go faster as he runs like normal, but most of the time when you move him again after stopping he'll go full speed when he starts running. This leads to a lot of cheap deaths. In addition, jumping is the opposite. Mario jumps slower that he's moving most of the time. This also leads to a lot of cheap deaths. As if this wasn't enough, Mario moves as if hes on a grid, making platforming a pain.
-ONLY 5 LEVELS AND ONE IS UNBEATABLE: Lastly, the game only has World 1 from Super Mario Bros. 3. After you hit the Question Mark Box and collect the mushroom at the end of the level, a 'The End' screen shows up and that's all. You get nothing more, nothing less, although it is nice looking. Also, Level 4 is completely unbeatable, so it's good that the map screen lets you go to any level first.
Is it worth playing? Sure! It is a pretty interesting bootleg, though the ROM is hard to find, but don't fret! I just so happen to have a ROM of it! As this is a bootleg and not a licensed game, emulation is legal. Download it here and give it a try!
i recommend using VisualBoyAdvance for Gameboy Emulation.
-Chris (site owner)