Ah, Shadow of the Comet, one of my favorites. That game gave me about 20 different heart attacks every time I tried to *spoiler* run away from the thing in the crypt *end spoiler* The sequel Prisoners of Ice is also quite good if you can find the english version, but you'll need to play shadow of the comet to play prisoners. In many ways Prisoners of Ice reminded me of Aliens a bit. =P

TWO games that are really great:

The Suffering,
Doom 3.

I already mentioned that. :bleh:

Reasons you do not let your children play the suffering.
-Child murder
-Language that puts "The Goodfellas" to shame
-Decapitation/Mutilation/Disturbing experiments/Blood

I know you did but mentioning games that are great, shouldn't be ignored - it should be awarded. The game rocks, and so does Doom3.

im not sure if Harvester can be counted-played it months ago,still have mental scar.Brr...
Although its more DISGUSTING(and funny) than scary

Games related to Cthulhu mythos are usually quite scaring (that is, Shadow of the Comet and Prisoner of Ice, and even Alone in the Dark, I think).
I also liked Veil of Darkness a lot, and you could try something of the Elvira series (I played Elvira II and it had some good moments) or Waxworks from the same developers.

Try Sweet Home for the NES, its known as the predecessor of Resident Evil.

You can find it at The Home of the Underdogs.

Dark Seed 1 & 2, Dracula 1 & 2 are all catagorized in Horror Section. Or maybe this LIST will help you choose something more appropriate.

Shadow of the Comet gets my recommendation as well because not only am I a rabid Lovecraft/Cthulhu fan, but it also is an excellent game.

Realms of the Haunting is a great horror FPS/Adventure title that you can find for relatively cheap on Ebay (I got my copy for $7 ;)). Wax Works is also a great (yet rather difficult) title that is recently added to our family of games so it shouldn't be hard to find.

Recieving my highest recommendation though is the Gabriel Knight series, simply sublime in everyway. ^_^