It's scary but not to that extreme lol. Its keen on jump scares. Bodies falling on you. Enemies busting out of the walls and air ducts. That stuff.
Now in my opinion, the first Dead Space is scarier (and harder)
Its the atmosphere. You're isolated in space on some huge ship, full of monsters and you don't know why. Your weapons are mere tools, your ammo in scarce supply. And the ship you're on is falling. Falling back to the planet. You have to fight for your life, fix the ship, and engineer your escape before its too late. Its worth playing for sure.
Dead Space 2 is less scary to me because you already know whats going on. That and this time, your character has dialogue. In DS1 he has 0 dialogue, and you never see his face, so you tend to put yourself in his shoes. That and in DS2 the weapons are stronger, ammo is slightly more plentiful, and you have a wider choice of weapons that fit any situation. Also your suits give you bonuses to your weapons, something that your suits in DS1 don't.
So yea if your computer can play it, I'd say go for it. And remember:

Go for the limbs...