Alex Kidd in Miracle World 

Continue mode cheat

At the game over screen Hold up and press 2 Eight times

Street Fighter 2 the World Warrior 

To select the same character in 2 player mode and also change the colour suit of the character

At the CAPCOM logo using player 1 control pad press Down, R, Up, L, Y, B and you will hear a sound that the cheat has been entered in correctly. Also the background will turn blue


Sonic The Hedgehog (Mega Drive/Genesis)

Level Select cheat

At the title Screen press Up, Down, Left, Right, Hold A and press start and you will see on screen a list of different levels to select.