Here are some cheats and tips for the game Mega Turrican.
Invincibility:
Pause game play and press A(3), B(3), A(3),
Start.
Level skip:
Pause game play and press Right, Left, Down,
Right, B, Start. To return to the previous
level, pause game play and press Right, Left, Down,
Right, A, Start.
Reverse D-pad directions:
Pause game play and press Up(2), Down(2), Left,
Right, Left, Right, A, B.
Bonus level:
Collect all of the diamonds in level 1. Continue game play
to obtain a score that has double zeros in any position (5900,
4005, etc.). Go to the bottom of the level and enter the elevator
that travels downward. Do not perform any actions that will remove
the double zeros from your score. Run to the right at the bottom
of the elevator shaft to access the bonus level.