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.

The Sims for the scrub-the-toilet mechanic.

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

DOTA popularized and also invented the battle pass mechanic.

Why hasn't anybody named Worl of Warcraft? They definitely made a shift in the mmorpg scene..

Or Tomb Raider for the first big budget movie adaptation.

I feel like Call of Duty 4 modernized and standardized the FPS genre on at least consoles. Every call of duty game still looks and feels exactly the same since CoD4 and every other first person shooter copied it's control scheme because it was so firmly cemented.

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

Rouge rougelike

Im pretty sure the actual, physical Trading card games like MtG and Pokemon gave us all these games with card mechanics in the late 90s/early 2000s.

Culdcept (1997), Baiten Kaitos (2003), Kingdom Hearts - Chain of Memories (2004). Then the card games weren't as popular for a bit, then the digital ones died out.

And then Blizzard released Hearthstone in 2014. I haven't played the other ones to know for sure, but I believe Yu-Gi-Oh Master duels crafting system can directly trace it's roots to it. Trade cards for dust of a specific rarity, dust from 3 can form a new card, Shiny cards give enough dust on their own for any card, etc. .