So if you haven't payed Metal Gear Rising, I highly recommend it. It's just the right balance of smooth, over-the-top action game and Metal gear melodrama. I thought it was ridiculously awesome and I was staunchly against the game before playing the demo.
As the game explains, Raiden's cyborg body has the bare minimum parts to keep himself as light and effecient as possible. That means he must extract electrolytes and reparative nanopaste from enemy cyborgs. After entering blade mode (the game's ninja-cutting bullet time) a small target box will appear. If you can hit this box, Raiden will yank out a fluorescent jelly-sac and regain all his health and energy.
Because of zandatsu (cut and take) Raiden can recover his health while fighting hordes of enemies without going to a menu or leaving to look for items and with some extra cinematic flourish. This is really cool unless you're me and start ripping nano-repair sacs out of everyone. Then every enemy is a slow-motion flippy death where Raiden's ripping out glowstick-organ after glowstick-organ of each and every guy around him.
The game also lacks a block button; the only way to block is to parry or sidestep, so the action doesn't amp down. Ever. If you like action games, Platinum won't let you down with this one.