Fairly standard game company interview in a big-company style. Recruiter phone interview, two-on-one phone interview with the relevant team, a Skype/HackerRank interview, then an all-day on-site. On-site starts with a panel with all your interviewers, then a full day of hour and half-hour interviews, finishing with a literal boss level (the HM and their boss). In League terms, you need to have your ult up for that encounter because it is the last-hit of the process.
Technical interview difficulty level is industry standard, not super-challenging. The people are easy to get along and very sharp. They love to hear about learning experiences, positive and negative, so have lots ready to tell. The campus is super-impressive even if you've been to other fancy offices, but don't get too much at the caf because that's when you interact with a peer group to help measure your cultural fit.
It turns out being player-focused at the level of individual developers is about making sure everyone plays League. The more League you play, the better. If you're more of a console gamer or don't happen to play League, you should play as competitively as possible (and try all game modes) for at least a couple weeks before applying and make sure the community doesn't drive you crazy. You're not expected to follow esports at all if you're not working on that side. If you can talk about playing the game and express your gaming interests clearly, they won't be too worried that you're not Level 30 and noone will care if you're stuck in Bronze. Below level 10 might be a little embarrassing though, and yes, they will ask about that and how you like to play League, just as small talk.
Communication with recruiting is very good, but the overall process was very slow. It's hard to get interviews and onsite scheduled, then you have to wait two weeks for the offer. So this might not be a good choice for a just-laid-off developer.