If all three NES Ninja Gaiden titles are fair game (no pun intended), then there are a few more items Ryu could get: Hourglass: Only in Ninja Gaiden 1 (like the Spin Slash). Freezes all enemies for a few seconds when picked up. I see this as being sort of like Bill's Falcon. Invincible Fire Wheel: From Ninja Gaiden 2 & 3. Not the version from NG1 that was basically just an invincibility power-up (we already have the Star for that) -- the actual sub-weapon that you could activate any time, but cost a whopping 20 ammo to use. Vacuum Wave: Only in Ninja Gaiden 3. Another sub-weapon which fires two wind razors that move in wave patterns. EDIT: I've noted this elsewhere, but he should also start the game with the Shuriken, like he does in Ninja Gaiden 2.