The scariest part of any game I've played is when you are drowning in sonic and cant find air. Its such a stressful moment

Resident evil wasn't that much scary either you know?  What they meant (you probably know this but I say it anyways) that after experiencing what the did, they were freaked out in real life too. It was their fear at that time. (I kinda agree with you on the Kirby one though...)
As for me, the first game that had me scared and freaked out was Parasite Eve. I was at my cousin house and my oldest cousin was playing it and I came in with my other cousin at the cut scene where the mouse/rat was mutating and transforming. For some reason I remembered it was growing bigger and bigger, and claws kinda just burst out the toe and fangs just popped out, blood and all as it did. Then when it was done it sniffed around and I thought it smell the girl and then it started running off at the first turn in the hallway though. So I was like "Whew, its gone.." Then when my cousin walked down the hallway it jumped back out and I was like "AH!" and left the living room. This was of course when I was young like maybe...5 or 6? (I don't remember) but a more modern game that had me pretty much scared the first time I played though it was F.E.A.R and F.E.A.R 2. I rented it both and brought it to my friends house and his friend was there too. We were suppose to play through both of them all night long, dark and loud. So we're playing and first time I got surprised was when I went into the dark part of the room where goodies were, armour and ammo. Turned around and little Alma was right there, me and my friends were like Ahhh, tried shooting her but she disappeared. Also it had moments where I actually didn't want to continue the game because I was kinda "frozen with fear", I'd stay against the wall or corner for a while then move on. I had to do that at the school, and in the underground works/sewers. School you're walking down the hallway then a strong wind blows toward you opening and slamming all the lockers and the lights were all burning out, it would flicker off and on. Except the one hallway were it wouldn't work at all. The sewer I went through a gate door to turn a valve and then was going go back out but the gate slammed shut and pipes from above fell down blocking me to push it and ghost and those monsters things start running at you from everywhere.

Well, when I was like 7 or 8... I liked to play Gun Smoke, an old game for the NES about cowboys... One of most scariest things of the game was that the enemies come from the NOTHING. That is, they just appear like nothing in the middle of the stage (on the game you walk from down to up, automatically.) The scary thing was that the enemies can appear while you walk without any problem, killing and taking you by surprise... And for make the things worst... The Death music was scary. O_o.