The extra detail you found cool in games...

[khanu]

In Legend of Zelda: WindWaker, it is the only game where when Link goes up steps, his legs actually get placed on two steps at once much like real life. All other games have un-realistic stair-climbing.

[Ad Bot]

[Maui69]

in URU you can find the telescope from Riven near the cleft

[Muzzles56]

in my game dozenrooms (dont bother, its not that great) you can climb into a vent and see the end-game enemy leave a room and head towards the playing area

theres also a room owned by the enemy and you can break a chest of drawers and go into a secret room, i thought it was cool

[querty67]

The music of Zombie Army Trilogy changes when completing objectives, surviving and etc
Zombies are somewhat smarter if theres a landmine in an open space avoiding it

[Foopster]

Romanes Eunt Domus in fallout new vegas

[Im_AFK]

in oot, the triforce was the central mcguffin; the very heart of the plot

in majoras mask, it seems wiped from history, with all oot characters reappearing in a parallel world.

then you learn about the four giants, whom those people worship
then you find markings of the triforce at the stone tower

[WaterOre]

When you first meet FLUUD in Super Mario Sunshine, you can see footage of Mario fighting Bowser in the lower left corner.

[ThatDarkNinja778]

The police radio in NFSMW is really neat. They would describe the make and color of the car you're driving, what area you were in, respond to certain actions you do (like crashing, stopping, hitting a police car, etc.), and also communicate with each other during the pursuit.

Ratchet and Clank cleverly masks loading screens with the scene of you traveling to the location you're going towards.

When you swim underwater in Banjo Kazooie the level music transitions to an underwater version of it.

In Super Mario Sunshine you can glance at some of the later levels in the background. Such as in Bianco Hills you can see Ricco Harbor down below if you look over the walls of the level.

[Element]

in black desert when it rains/if you're in water your character becomes shiny and wet, same happens if you carry around heavy items, your character starts sweating, also the shoals of roaming fish which makes fishing more realistic

in gta5 when you follow a single npc around, they start to walk faster and look behind their back more, eventually getting more paranoid and i think they eventually run away