Metroid
For creating or at least popularising the platform-adventure genre (metroidvania is a dumb name for the genre).
That's because 'Metroidvania' isn't a genre, it's a game design aspect, like 'open-world'. While it's mostly used with platformers, it can be used with other genres.
I think King's Quest is probably the single most important video game in terms of evolving the industry. A very good game + new ideas and concepts + very popular = completely changed how both gamers/devs looked at games.
# Fantastic to look at (for a 1984 game)
# Not a very good game (not even by 1984 standards)
# A great leap forward for the genre of "Adventure games" in 1984 (known nowadays as "Interactive Fiction")
# Very popular at the time
# Not really introducing anything new
It is an important step forward nevertheless as it made a turn-based genre real-time and more immersive as a result, but in No Way does it deserve a nod as "the single most important video game in terms of evolving the industry". There are plenty of other games deserving of that honor.