From publisher blurb:
Sure it's an easy matter to keep track of hit points. Sword stabs for 3 points of damage and character's hit point total is reduced by 3. Sword stabs again for 5 points of damage and hit point total is reduced by 5. And on and on until the character either is healed or reduced to 0 hit points. This is a perfectly acceptable system and one that needs to changes to work.
But let's say you're looking to run a "low fantasy, gritty, violent" game. Let's say you're looking for wounds that bleed.
Wounds, Bruises, and Blood presents an optional system in which not only is hit point damage tracked but each individual wound is tracked. That sword stab for 3 points of damage now has a chance of bleeding if it isn't properly cared for and, even if bandaged, there's a chance that the stress of combat will re-open the wound at a later time.
Additionally, under this system magic damage -- if uncared for -- continues to eat away at the target for hours after the attack and bludgeoning attacks can cause disfiguring bruises and potential loss of strength and flexibility to battered and broken bones.
And healing is no longer a "heal hit points and move on" process. Under this system, each wound heals separately -- a truly deep gash, for example, may require days or even weeks to heal.
With "Optional Options" scattered throughout this PDF, DMs can tweak and customize the system to suit their needs. Overall, though, the system is fast to use and adds only minimal record keeping to the game.