It just has better production values.
Garcia Hotspur, a demon hunter whose accent is every bit as ridiculous as his name, travels into Hell to save his girlfriend Paula. It's not a subtle interpretation of Hell, either -- in the demo, Garcia literally enters a building with a giant neon "Welcome to Hell" sign on it. He's joined by a demon who has decided to work on the side of good (or at least Garcia), who manifests as a flaming, floating, inexplicably British skull in cutscenes, and as Garcia's weapons in gameplay. Those weapons include the "boner," a pistol that shoots bones (no, really), a shotgun-type weapon, and a machine gun, neither of which are called the "boner" so I can't remember the exact names. Garcia's jacket (a stylish leather one with "Love will tear us apart" on the sleeves) changes colors to indicate which weapon he's holding. He also carries a gun that shoots light, which has a very specific use.
One more time, and then we can go back to our grown-up lives: "Boner." Hee hee hee. Ahem.
The hellish enemies that Garcia faces -- mostly featureless, zombie-type things, with the occasional Pyramid Head-looking blade-wielder -- are covered in inky blue "darkness," and can't be harmed in this state. You have to give them a good blast with the light gun before the darkness sloughs off and they are vulnerable to your melee attacks, puerile armaments, and totally awesome QTE finishers.
This "darkness" mechanic is central to the game. Not only are monsters tucked safely in their cozy Snuggies of evil, the area will frequently fill with an oppressive blue mist that progressively damages Garcia. He has to either heal himself with giant heart powerups, light the area (by shooting at goat head statues with his light gun) or destroy the source of the darkness (in the demo, a giant hand with a disgusting gash that shoots darkness bubbles) to save his life. This darkness also has a puzzle component: one door won't open unless it's shot from within the darkness, forcing you to go to a certain area and trigger a slowly advancing wave of blue evil. Then you go into the darkness, and shoot the gate, so you can pick up the brain and eyeballs some baby-headed doors want to eat before they'll open up for you. Of course.
The "darkness" gameplay hook is a strong one, and adds a puzzle element not usually seen in Grasshopper action games. Also unusual for Suda action games: this level of polish. There didn't seem to be any rough edges in the gameplay -- which, even Suda superfans will admit are usually present. This time, the quirks are all intentional.