Every XCOM Enemy Unknown cutscene is excellent, and the best ones give me goosebumps every time.
Shooting your way out of the Silent Cartographer in Halo 1, when the music kicks in.
Nearly every story relevant moment in Halo 3.
Actually every story relevant moment in Halo Reach.
When you watch the instant replays in Bejeweled 3.
The ambush in Black Mesa, when the come through the skylight.
Moving through the apartments in Half Life 2 towards the suppression device.
Breaking into and back out of the citadel in Half Life Episode 1, along with the underground and the hospital. Shame about that ending battle though.
The whole of Half Life 2 Episode 2.
Bioshock Infinite, in the cutscene where she saves you with the zepplin. I was really upset when the game ended because it meant I wouldn't get to listen to the characters talk since it was over.
In a high chaos run of Dishonored, Samuel the Boatman alerts the guards that you're coming when you do the final mission. Excellent detail, which made the whole level so much cooler.
The first time our group had ever escaped Chernarus in Arma 2 and Arma 3.
Stealing two armored SUVs from an enemy radio base in Arma 2 Escape Chernarus, and speeding them towards Green Mountain as enemy jets fly overhead. The lead vehicle loving detonates, rear vehicle (which im in) dismounts and scatters. I've never seen a legit rout in the face of overwhelming force in a multiplayer game, but there it was.
The first time I lost a colony in Rimworld. And the first time I made it off the planet.
Playing The Hidden: Source which is a style of game I've never seen anywhere else.
OpenXCOM (XCOM from the early 90's, modernized) with the FMP mod. The first men in black mission was absurdly brutal, and it led the tensest and most drawn out firefight I'd ever had in the game.
In Rollercoaster Tycoon 1 and 2, when you won the level objective all the people stopped where they were and clapped. The ensuing balloon apocalypse is something I'll never forget.
Far Cry 3 when u touch the tiddy