I'm still puzzled by the direction the game is taking. The main themes of the first game were 1) Near-total isolation in a hostile environment, 2) Fear of an incomprehensible unknown, and 3) The empty and lethal void of space as an environmental hazard and constant threat. The first game excelled in presenting these themes, despite the shooter-nature of the game working against it. After all, it's hard to be terrified of space zombies when you have a gun that fired telekinetic razor blades that slice and dice anything that comes within a 5-foot radius. Even with that, the game series was very well received.
The second game faltered in presenting those themes with the inclusion of semi-helpful allies who seemingly contributed to your success (compared to the first game where they were exclusively detrimental, or only gave you missions to complete). They also reduced the fear of the necromorph threat by explaining certain aspects of its nature, creation, and by implying that there are means of control. The game did, however, excel at making space itself a threat, with the inclusion of breakable windows and prolonged sections without easy access to oxygen. The space-walk sections in the middle of the second game are great examples of this. The second game also focused on the theme of madness, both in Isaac and Strauss, and presented Strauss as a parallel of what could become of Isaac if he did not conquer his madness.
The third game tosses all of these themes out of the window. Co-op gameplay removes the feel of isolation considerably, from what I've seen. It also impacts gameplay, since there are no longer any blind spots in the players' collective vision, should they stand back to back. By this point, the Necromorphs have been completely explained, and as Lovecraft put it, the greatest kind of fear is fear of the unknown. Finally, the void of space has been removed, with the game transitioning to an ice planet. I cannot say how much this particular theme's absence upsets me. It removes one of the core principles of the game series, as well as the element that scared me the most. Necromorphs be damned, nothing was scarier than walking in zero gravity, looking for a way out, Isaac's breathing becoming more and more ragged over time.
Dead Space 3 is ignoring the elements that made it WORK. It's like Bioshock 2's transition to a combat-focused game with minimal horror elements. In an attempt to reach a new demographic, Dead Space 3 is just hemorrhaging consumers.