After getting access to Ninja Gaiden, play the game on very hard. When on Chapter 4 and you're in the Clock Tower Plaza you will see a door with a pink jewled eye. Above it will be a platform with a chest. Make you way up to the chest. Once there turn around and you should see the Clock Tower. Shoot the face of the clock with your arrows and another chest should appear next to you. Open to find (Ninja Gaiden 2: The Dark Sword of Chaos). Ninja Gaiden 3: The Ancient Ship of Doom is in Chapter 10. Once you enter the Hall of Balance. Enter the door (not the one behind the waterfall) and when you get into the room run to the right and inbetween the two podeums do a Flying Bird Flip to reach the top. There you will find Ninja Gaiden 3 rather than the previous Scarab that was there. Whoever said you had to get Master Ninja in every level should have wished they known this !