Being 1 or 2 kills away from getting a nuke in MW2. My hands start shaking and it feels like I get butterflies in my stomach. Hated those moments but it all went away as soon as I get the nuke.
Smash Bros 4. The thing that gets me jittery about it is that you never know who you'll be playing against online and you have to get a good read of the player and always have to be on edge. Especially if you play competitively
My first playthroughs of Dark Souls had me jittery out of caution and anger while playing. After you play it so much though it seems like it's on super easy mode.
Context: I have a panic disorder, so I tend to panic and freak out easily ESPECIALLY when it comes to video games. I get way too focused way too easily. So let's start down the list. Garry's Mod: I've never played TTT (yet), but I used to frequent Murder. Let's just say that wasn't a good fit... I shouldn't be allowed firearms in a room full of innocent bystanders. THEY ALWAYS FOLLOW YOU AND WALK TOWARDS YOU AND IT'S SCARY so I shoot them in the face. Obviously I quit that game mode...the paranoia. I also had a friend who I played with very often who was the stealthiest murderer ever, and he just made a game out of following me and appearing out of no where with a knife in his hands to scare me (there was no timer) so he could listen to me scream and cry and panic in Skype basically. Dying Light: When I first played dying light, I had NO idea how to play and hadn't taken my medications at all that week, not a good combination. I was originally very against modern consoles, I mean I had a DISTINCT preference for the retro or PC, and refused to pay for a PS3/PS4 or a 360/One, so I hadn't played a current gen console since I was a kid. First game I played after I got a PS4 (long story on why I changed my mind) was Dying Light. Had never played a horror game previously, hadn't even played a recently made game since ~'04 because I spent most of my days on WoW. Holy shit. My reaction when the zombies were coming after me and the only weapon I had was a table leg AND I DIDN'T KNOW HOW TO PARKOUR?!?!? I sat there and laughed while crying for about 20mins. Not one of my finer moments. But to be fair, I was invited into my friend's game which was already completed and the difficult zombies that come later in the game were spawning...and it was my first time playing. Volatiles are scary guys. Minecraft: First time ever playing, the zombies were traumatizing. I know what you're thinking "Oh hey, she was probably young when she started playing since it's an old game!" No, I was 18-19ish. I JUST WANTED TO BUILD A HOUSE. Thought I'd get too bored in Peaceful mode. RIP. Also the Creepers appearing out of nowhere made me feel uncomfortable...and scared. GMod (continued): If I play a new map in Deathrun and die suddenly, it scares the hell out of me because I didn't know there was a trap there. I'll just be like "oh hey, there's no traps here so I can walk freely for a bit-- OH GOD WHAT" Five Nights At Freddy's: I tried playing it after I took my night medication which impairs my judgement and makes me extremely paranoid to start off with. I was like "Pfft, nothing scares me!" And then I saw one of the characters move and I panicked and closed the game. I think I was 2mins in. Tops. Haven't tried since. Sinistar: I have an arcade, and one of the original game cabinets is Sinistar (early 80s I'd say). The Sinistar character is so so so so so so scary. "Oh hey, I'm going to mine these planetoids and shoot these ships!" and then you hear his voice... and see him coming for you... If you don't know the terror, look it up. It gave me nightmares as a kid and still bothers me to this day (love the game though). There's a lot more, so I'll add to this another day.
Games that make me jittery Starcraft & Brood War Expansion The beginning levels don't get me quite worked up, but once you get late in the game, it gets frantic trying to tech your way up and build up your forces knowing that the enemy AI is going to hit you hard and rape you to the whorehouse and back if you're not prepared. The Binding of Isaac & Wrath of the Lamb DLC BoI is hard. You really don't have a lot of health, and that only gets worse when you reach The Womb as enemies deal double damage from there on out. With the game randomized, there's no real way to prepare for whatever might be thrown at you. Sometimes you get lucky and the room is spacious with enemies you can easily deal with. Other times you have little to no maneuverability room and the enemies are a pain to deal with. When progress into stages like The Womb and onwards, you start to encounter Bosses from the previous areas that now serve as mini-bosses. To top it all off, if you die you have to start all over again. DayZ I currently play the mod, but I guess this would also apply to the standalone as well. Zombies in the game aren't really difficult, they never attack you so long as you keep running. Once you lure them into a building they start to walk at a slow pace, making it easy to just walk up and kill them with a melee weapon. The real threat is from the players, who you will never know where they are. You will never know if you're safe walking through that open field, and at any moment your ears could get raped by the unsuspected loud noise of guns being fired. This is especially true in the airfields, Cherno, and Electro.
FEAR 1 and 2. I can handle horror, thats fine, but when I am in the middle of a massive firefight and walk down the next hallway and you drop a jumpscare on me for NO REASON but to just mess with me! IM NOT HAVING A GOOD TIME.