Sonic Blast on the Master System is basically an "Official Pirate". It was released in Brazil under TecToy, who have the rights to still create and sell old SEGA systems to the Brazilian market. They also do a lot of dodgy ports, like Duke Nukem 3D for the Megadrive.

One port they made was Sonic Blast from the Game Gear to the Master System, which went well besides the miscolourations.

Due to the much smaller palette, the Master System couldn't handle everything correctly. Even on the title screen you can see the lack of 'shiny' between the above MS version and the Game Gear version to the left.

 

Submitted by: Rlan

As a quick comparison, this is the emerald from the beginning of the game, the left being the GG version, the right the MS one. The GG palette makes it all the better.

 

The levels also lack in colour and features. The background for the MS version of Green Hill Zone is very basic, one shade of blue. The rock is also more yellow then it should be.

Also, the "rings" icon is stuck in a little lower than it should be. This is because this is where it is in the GG game, and they wern't able to move it. They simply expanded the sides.