Darius Gaiden

Extra Credits
Press X, A, Left Shift, Right Shift, left, then hold down Left Shift and press X, C, Z, A, right, right. You should hear a sound if done correctly.

Easy and Harder Game
At the options menu Hold down X, then press Z, C, Left Shift, B, left, Right Shift, Left Shift. You should hear a sound if done correctly.

Turbo Fire
At the games options screen hold B and press Y, right, left, X, Z, Left shift, Right shift