Well this kinda came out of nowhere.
Best to know as little as possible going in, but if you like fun, violent, "here's some very specific rules you must follow or you die" kind of plots you're going to have fun. It's blood spray violent, not Saw-level gore and very akin to Battle Royale.
It's a bit silly, has some very good stakes in each episode, and way way better than it has any right to be.
Some googling it looks like it's based on a manga so it has some weird based on a manga vibes, but it's much better than any other adaptation I've seen.
Currently on Netflix.