Interesting puzzle design mechanics coupled with solid game-play make this much more than your average shooter.
Garcia moves well enough and can dive roll away from attacks easily. The action is viewed from over Garcia's shoulder in a similar way to Dead Space. Gun attacks are launched by aiming then firing. The ex-demon Johnson serves as his companion and transformable weapon, although he is usually carried by Garcia in the form of a torch. Firing without aiming first will make Garcia swing his Johnson-torch in the enemy's face. The torch can be charged first to blow away low-level demons in one swing. Johnson can transform into a small variety of gun forms; a pistol, a shotgun and an SMG. As you progress through the game, each weapon upgrades and acquires new features. Later the pistol fires bombs, the shotgun fires grenades, and the SMG rounds home in on targets. So while the weapon pickings seem sparse, their extra features are constantly useful, and sometimes necessary. You use ammo rapidly, but you can rearm from the numerous ammo boxes all over the place. Each weapon form uses different ammo.
Another function of Johnson's weapon forms is the light-shot. You see in hell, or this game's version of it, there is light. Then there's the dark, which is just the absence of light. Then there is the Darkness, which is sort of like anti-light. When the Darkness floods an area, Garcia has limited resistance to it before it begins to eat into his health gauge. Darkness sticks to demons however, and this makes them invulnerable. That means when both Garcia and a demon are inside a zone of Darkness, the demon has an overwhelming advantage. The light-shot can dispel the Darkness from demons, so long as they are not inside a Dark zone, and can also stun demons once they are vulnerable. The light-shot can light lamps to repel enemies and light your way, and trigger certain gates to open or close. The light-shot can also light up goat heads on the walls, which serve as light sources and repel the Darkness from the local area.
Beyond this however, is where the demons get clever. The Darkness is hazardous to your health and makes the demons invulnerable. So you would think getting rid of it should be your priority at all times. There are some doors that are blocked by demon vines, and the vines are connected by a cable to a special crystal. Smash the crystal and the door can be opened. Unfortunately, the crystal is usually hidden, cannot be destroyed unless you are in a Dark zone, and the cable is invisible unless you are in a Dark zone too. Sometimes Darkness descends on you without warning, but other times this kind of mechanic forces you to enter the Dark zones whether you want to or not. And some Darkness is so thick you cannot dispel it, so frequently you will have to commit to charging through the Dark zones hoping there's light at the other end.
This constant seeking-out of light then Darkness is responsible for the game's puzzle mechanics. But the bosses also use similar tricks, requiring you to let them bath you in Darkness, then shooting their now-exposed weak point. Red glowing things are always weak points, but they are not always visible. No boss in this game is as simple as shooting them in the face. Indeed some normal enemies are also impervious to being shot in the face and need more advanced tactics to kill. It's working out exactly what you are supposed to be doing to kill the enemy, although early on Johnson gives hints to push you in the right direction. Even though the enemies and puzzles sometimes stump you in the heat of the moment (usually when the Darkness descends) they are never cryptic. It's just a case of knowing the trick, and the trick is usually round the next corner had you had enough health left. Because the Darkness can drop in anytime, the game makes you feel as though it might at any moment, which creates a constant tension in the background.
Shadows Of The Damned wouldn't be much more than a Dead Space clone, if it wasn't for the interesting way the game constantly throws new challenges at you. And the game does constantly throw new and different challenges at you, even when you think you've seen everything.