氪肝

kègān
(slang) to put in long hours, typically late into the night, playing a video game (rather than pay for power-ups)

CEDICT

slang

Entry Composition

1 氪 kè krypton (chemistry)
2 肝 gān
  1. (slang) to put in long hours, typically late into the night, playing (a video game)
  2. (of a video game) involving a lot of repetition in order to progress; grindy

classifier: 葉