That's game 

An phrase used and likely originating from pro gamer JESSE JO MARTINEZ, as early as 2006 in Guild Wars 1 or 2010 in Heroes of Newerth, when a game, match, round, or video game is near or about to be over, and you or your team are winning or losing. Usually it gets mumbled in frustration or in excitement over voice comms.

*Team A just did something stupid, giving Team B the lead. "That's game, we lost bois."

*Team A just did something really awesome near the end of a game turning the game into a win shortly after. "That's game. That's GG. We won this easy."

If said before a game is over in all chat, will be interpreted as you being either demoralized or wanting to concede, or confident you've already won the game.

That's game by JesseJo July 5, 2021

that’s game

a way of proclaiming victory. usually used in sports when one teams makes a play that guarantees victory.

‘He scored a go ahead touchdown with 8 seconds left? That’s game, dude!’

that’s game by Are11 July 2, 2023

What's That Game With The X's and O's? 

A friend who forgets what Tic Tac Toe is.

Friend: What's that game with the x's and o's??
Me: are you kidding me-

What's That Game With The X's and O's? by A Kid From Math Class December 16, 2022

But that's just a theory, a Game Theory! 

Most commonly used by MatPat, owner of the Game, Food, Film and Style Theory channels.

Used at the end of videos to remind people that he is just making theories and might not correct.

*MatPat finishes talking about his Theory* But that's just a theory, a Game Theory!

But that's just a theory, a Game Theory! by BlazingBeast September 23, 2023

That’s Just How the Game Go 

A phrase used when something doesn’t go as planned. This phrase is often followed by a shrug while saying.

Employee: "I’ve put all my hard work into this company and they still haven’t gave me no raise yet. Got these other workers sitting on they behinds getting raises for not doing a damn thing while I’m carrying all the weight. I’m so sick of this sh*t!"
Me: "Hey, that’s just how the game go"

That’s Just How the Game Go by thatboymally June 13, 2021

And now that's how you game 

Something shabnam says

"And now that's how you game"
Wow i like that phrase

And now that's how you game by thecharacterwannie July 10, 2022

buggar that for a game of soldiers 

I wouldn't even think about doing that
that is too godawful to even think about

you want me to be your training buddy for the marathon... buggar that for a game of soldiers!

buggar that for a game of soldiers by duck_man June 11, 2006