Games

Souls games. Popularized invasions.

DOTA popularized and also invented the battle pass mechanic.

Metroid, which spawned more than half of all indie games.

Don’t know if this counts, but Resident Evil 4 killed off the tank controls and single-handedly popularised third person cameras for survival horror games.

Serious Sam The First Encounter claims to have invented event cued music. Ie, intense fight music stops once an encounter is over.

Quake is believed by many to have invented Rocket Jumping, but Marathon (1993) had two forms of it first.

Marathon and Rise of the Triad both released with duel welding pistols in the same week.

Skyrim for the horse armor dlc.

Rouge rougelike

Dune 2 for it popularized RTS genre. C&c to bring it to the masses

The Sims for the scrub-the-toilet mechanic.

People always forget that resident evil 4(? There is a million of them) made third person shooters mainstream.

I'm surprised I haven't seen anyone say Pokemon. From a. monster collecting/battle game nothing has really came close.

Note: read "first" as "first popular/important", not just for this thread but for most conversations across media like this.

Spelunky was the first "Roguelite" that brought permadeath with meta progression to another genre, starting the modern wave of Roguelites.

Pokemon kicked off "monster collection" as a mechanic

To my knowledge, Halo was the first major game to do regenerating health