There are limits as to how scary a demo can possibly be, so it's important to keep in mind that the trial which Dead Space 3 offers is more meant to deliver on a gameplay level rather than an atmospheric one.
Picking up just at the start of Issac's crash landing on the necromorph-ridden planet of Tau Volantis, the demo is broken into three different gameplay show points: Single player, multiplayer, and weapon crafting. Each of these points is meant to dive into the new features of the franchise rather than show off any major plot points. And from that perspective, the demo is largely a success. Fans of any co-op shooter may be happy to know that the action in Dead Space 3 is definitely up to snuff.
Of the three modes available, the weapon bench is the most interesting, as what you use to fight off necromorph determines better what kind of necromorph you'll have success against. Whether it's a nail shotgun with rifle attachment, the line cutter with plasma bolt, or an electric blade on an assault rifle, the weapon swaps almost never fail to amuse. Also, when you take into account that a player is able to hold two different kinds of weapons at any given period, this means you'll have a potential for four necromorph slaying weapons at any time.
Add in a second player and it's easy to see how it's possible to have gear for just about any situation, which wouldn't normally be an issue if Dead Space 3 was gearing to be a primarily action oriented title.
The problem is that with an extra player in the mix there's very little challenge, and unless the full version of the game features more strategic enemies (or alternatively two to three times more things to fight), the combat quickly becomes boring. A fantastic example for this potential issue is the drill portion of the demo, which pits players against an out of control rotating drill while being swarmed by various types of necromorph. Alone, the encounter is pretty rewarding, and fighting off enemies while trying to take out the drill's weak point is a fairly engaging task. But with the addition of a second player the encounter is almost trivialized, with one player able to easily hold off the undead while the other can focus entirely on the drill.
Knowing someone is there for you, even to announce an incoming enemy, takes so much tension away from the event that it's like playing an entirely different demo. In fact, playing in co-op is quite literally an entirely different demo.
New cutscenes, added quick time events and the promise of unique missions mid-game all make co-op the obvious choice, which is incredibly disappointing. Perhaps this is an issue that is unique to the demo, but when given the option between more content, but easier encounters and less content, it feels like the player loses either way.
It would have been great to see moments of gameplay where Issac and John enter a breakdown, or anything to further accent where the horror theme was the primary focus rather than the action.
The impression Dead Space 3's demo leaves is certainly a good one and I can't stress enough that from a design perspective focusing solely on the gameplay, the amount of work that the developer has poured into combat is apparent. The shooting is smooth, dodge rolling is fun, the weapon customization is satisfying and superbly imaginative, and that's all taking into consideration that this is only a small fraction of what the game has to offer. But the horror fan within me asks at what cost? Few points within this demo even hit close to the tension provided in the previous titles, and given how often the Dead Space franchise throws the Hollywood shock scares at players that should paint a pretty bold picture.