Pause the game and type 'LARSXViii' for infinite credits.
Hold down left mouse button while typing the above to enter
the colour mode which is controlled via the numeric keypad.
Press 'Q' while the game is paused to enter the music mode.
When the shinobi logo appears hold down the letter 'T' and
move the mouse to control it.

Hex cheat:
Go to dir where you installed. For cheats in this game, use the
DOS utility DEBUG. First backup your game to be edited, then
type the following from the dos prompt:

ren c:\shinobi.exe cheated.cht
debug c:\cheater.cht

For infinite lives, type:
e ce1 90 90 90 90

For infinite magic, type:
e 54a3 90 90 90 90

To stop timer, type:
e 6b19 eb 8
w
q

Then rename CHEATED.CHT back to its previous name.