It might be silly but have you tried closing other tabs? A friend if mine brought up that computers tend not dedicate much processing power/cores to internet tabs since they are usually low intensity. Even if there is an embedded game.
Yeah, I even installed Thorium to see if that would help lol. It's not much of a issue though, I was able to play the game and that's what matters the most. I just thought I'd let you know about this issue... Unless you're not having it, that would be weird. xD
Thanks and good luck with future releases. ;p