There are distinctions, sure, but at no point in MY life has "beating a game" been equated with "100% completion of every piece of available content in a game".
Going all the way back to the 90s, if you beat Robotnik in Sonic 2, you beat the game, even if you didn't get all the Chaos Emeralds.
If you beat Bowser in SMW, you beat the game, even if you didn't finish the secret levels and unlock fall.
In FF7, if you beat One Winged Angel Sephiroth, you beat the game, even if you didn't do Emerald/Ruby Weapon or breed a Gold Chocobo.
If you beat Majora but didn't get all the masks you still beat the game.
If you finished Baldur's Gate 2 and defeated Irenicus you beat the game.
If you beat the Elite 4, you beat Pokemon, even if you didn't collect all 150.
If you went Act 1-4/5 in Diablo 2 on normal, guess what, you beat the game. You can beat it again on Nightmare, and again on Hell, but you still beat it.
Did that change somewhere along the way? I beat Spider-Man. Did I 100% it? No. I beat BotW and ToTK. Did I 100% them? No. I beat God of War 2018. Did I 100% it on the highest difficulty? YES, but I beat it first!
There are distinctions, sure, but at no point in MY life has "beating a game" been equated with "100% completion of every piece of available content in a game".
Going all the way back to the 90s, if you beat Robotnik in Sonic 2, you beat the game, even if you didn't get all the Chaos Emeralds.
If you beat Bowser in SMW, you beat the game, even if you didn't finish the secret levels and unlock fall.
In FF7, if you beat One Winged Angel Sephiroth, you beat the game, even if you didn't do Emerald/Ruby Weapon or breed a Gold Chocobo.
If you beat Majora but didn't get all the masks you still beat the game.
If you finished Baldur's Gate 2 and defeated Irenicus you beat the game.
If you beat the Elite 4, you beat Pokemon, even if you didn't collect all 150.
If you went Act 1-4/5 in Diablo 2 on normal, guess what, you beat the game. You can beat it again on Nightmare, and again on Hell, but you still beat it.
Did that change somewhere along the way? I beat Spider-Man. Did I 100% it? No. I beat BotW and ToTK. Did I 100% them? No. I beat God of War 2018. Did I 100% it on the highest difficulty? YES, but I beat it first!