If you’re aren’t OK with giving up your eyes or spinal cord in Soul Sacrifice, you can make a weapon out of vegetation. A Plant Sword can be created by sacrificing a Sword Sapling. When you strike an enemy, the Plant Sword stiffens up so you can slash away. Might not be the most effective weapon, but it beats chopping off your arm.
The Thunder Axe looks like a stronger weapon and you can make one of these by offering a Razor Thunder Stone. This axe is imbued with electricity and dishes out heavy damage.
Soul Sacrifice has monsters like the Griffin to battle. Sony Computer Entertainment has Soul Sacrifice slated for release this winter.