This is actually a good question if I'm answering it entirely based on feels, not actual data.
Biggest game overall, single player plus multiplayer? Halo series. Maybe Destiny 1&2 too.
Biggest PC game? Probably Neverwinter Nights (2002). (This predated Steam, so fuck the statistics anyway.)
Biggest game I'm spending shitloads of time right now? TRAIN SIM WORLD 3.
There are a lot of people who go "I tried to learn X through Duolingo and failed". Sure, that's probably true, because staring at the app is not how language learning works. Much like 100 years ago, people would have said you can't learn a language by reading a single book.
Duolingo is great for basics of the language, vocabulary and constant daily lessons. But you always need more. There's a whole language sphere out there. People actually using the language and whatnot.
I started studying French through Duolingo and about 6 months later I was like "I really need a grammar book and a dictionary, dammit". Year in, I was like "I should try reading news in French and maybe try a book."
It's funny, the only Linux software I've ever used that was only shipped as binaries was Loki games. Also, the only software that broke after binary compatibility went south. There used to be a giant tarball of old libraries and jiggerypokery that enabled the Loki games to sorta kinda work.
I was kind of sad to see that Sid Meier's Alpha Centauri didn't run too well, but then I tried to play the GOG version on x64 Windows 11 and there are occasional weird issues. So, eh.