“You said it yourself, big bro.” [She smirks.] “My little sister is pretty good.”
“Shut up. I’ve almost got the pattern.”
[Miu snatches the console, beats the boss in 10 seconds, and hands it back without a word.] My Little Sister is Pretty Good -Final- -DomiHo...
It looks like you're referencing a specific title or fan work:
[Black screen, white text:]
[Small post-credits sketch: Miu waking up and yelling, “DID YOU JUST CALL ME ‘PRETTY GOOD’? THAT’S IT? NOT ‘AMAZING’?”]
“…Show-off.”
“But yeah… she’s pretty good.”