Pong defined the decade, but Space Invaders helped define the medium.

I'll add the 1975 Game Of Dungeons to the mix, being the second computer RPG and the one who all current RPGs can trace their roots to.

It's a fundamentally multiplayer Dungeon Crawler running on a mainframe at the time (and still works today!), with character development levels that seem incredible today (In one screenshot, the CRPG Addict has over level 1000 and over 12000 hit points, defeating a level 372 demon being decried by the game a being a pushover to his character)

I'm giving Breakout my subjective vote, based on that I've spend most time playing similar games.

One that could be added to this list is Akalebeth: World of Doom (aka Ultima 0)

I personally enjoyed Breakout the most. 2nd place goes to Gala and 3rd to Oregon Trail.

Pong pioneered, but Space Invaders is where its at.

Space Invaders is clearly the superior game, but Pong should get the nod here due to its importance. It was arguably the first killer IP, and made home console gaming a thing. It's the forbearer (console wise) of them all!

*Looking at the results...*

Doesn't look like there's many who know early computer gaming history, only arcade and console history. Otherwise games like colossal cave and Zork would have many more points

Yeah, my thought exactly. As far as I know Collosal Cave Adventure is the first adventure *ever*. Every adventure game - even Zelda - owes something to this game. Zork massively popularized the genre.

I am also wondering about the low votes for Oregon Trail. This game is highly influental.

I also would mention MUD from 1978, the first big online multiplayer game.

In terms of being the biggest commercial hit of the '70s, Space Invaders is unquestionably the correct answer. Way bigger than Pong, Space Invaders was the title that truly brought gaming into the cultural mainstream. Pong established a niche gaming community. Space Invaders took it mainstream and made gaming a mass phenom.

In the more subjective measure of what '70s game I personally liked the best though, that would definitely be either Zork or The Oregon Trail. As a child of the '80s, I'm a bit partial to the latter, as a version of it was in fact used as an educational tool in my own school. Nostalgia bias for me there that doesn't exist for games like Space Invaders or Pong.

Space Invaders is what I enjoyed the most.