He spent a lot of money on microtransactions in this game.
Tips
usage
In Chinese internet slang, 氪 (from 氪金 kèjīn, 'krypton gold') means to spend real money on in-game purchases. 氪金玩家 (kèjīn wánjiā) refers to a 'pay-to-win player.' This usage comes from a Japanese mobile game.
culture
The slang sense is extremely common among young Chinese gamers. 微氪 (wēikè) means 'light spender,' 重氪 (zhòngkè) means 'heavy spender,' and 零氪 (língkè) means 'free-to-play.'