I forget how many chapters there are in DS1, I want to say something like 6 total? Anyway, DS2 is "more of the same," which isn't a bad thing, but you see more people in it that aren't giant monsters or something - and Isaac talks. That last bit breaks it for some people, but he doesn't talk a whole hell of a lot.
If you want to get yourself more immersed in the whole Dead Space atmosphere, I think both of the movies are on Netflix right now, if you have it. I know I saw Aftermath (which takes place before or after DS2, I forget) a few days ago, and Downfall takes place before DS1.
During that grinder sequence, where there were Necromorphs spawning, every time they hit you, it felt like they did nothing at all against your health. The enemies felt very spongy as well, not like in the previous games, where their limbs burst off when you've shot enough rounds into them. The first mini-boss felt forced.
The ice planet looks beautiful, but it doesn't give me the same feels as DS1 and DS2 did. Neither do the introduction of enemies with guns or human enemies. --- Spiders. Spinnen.