Ironically I was just replaying through Dead Space 1 myself. Honestly speaking, it's a good game, but I personally have never really found it scary, and I think it suffers from a sort of tedium the sequel fixes. I think there's some nice little touches, I agree there, but I think what takes a lot from the first Dead Space from me is this sort of rhythm the game has. I can't quite put my finger on how to explain it, but while the game isn't super repetitive or anything, there's this pacing thing with Dead Space 1 where it'll go through the same sort of 'beats' over and over again. I can never find myself able to play Dead Space for more than a few hours, not because of fear but a tedium the game has in extended periods, despite being a person who beats several 8-12 hour games in one sitting several times a month. I don't have this problem with the sequel, and I personally enjoy the sequel more. I know the first one is 'scarier', but I've never really found it scary, fun yes, but not really even creepy, more... Interesting? It can have tense moments, and some startle moments, but the horror feels too... Flashy, I guess? Like it doesn't feel organic. Ironic to use that word due to what Dead Space is all about, but it feels more like spectacle horror at times than true horror. Which isn't bad, but then it employs all of these techniques from horror games that rely on the game scaring you or catching your interest with other elements, and for some reason I just find those elements to be absent in Dead Space. The art direction is good but I don't find the locales particularly interesting or having key intrigue elements like Silent Hill. I don't find the atmosphere to be all that creepy. The puzzles aren't particularly great, the game has some fun mix-ups with Zero-G, stasis, kinetics, and such... But I feel Dead Space may be too focused around its Necromorphs.
This is always hard for me to describe, it is an action-horror game, but I don't know... It just feels like... The Necromorphs are interesting enemies, and the game is ace in some areas like UI, some subtle details. But it almost feels like instead of making something greater with that they settle to rely on the same few tricks over and over, and make a solid action-horror game, but miss out on what could be so much more. Dead Space 2 takes it in a more action-y direction, but I think is paced far nicer.
Many likely won't agree with me, and that's fine, but I always have had these weird split thoughts on Dead Space 1 I can never quite explain.