Looking for a "squid game"/"ORV" type manga/manwha I read some time ago

I believe it was a manga.. but I could be wrong.

I remember it started with a bunch of people finding themselves in a big room, not knowing what happened. Then someone from a big screen starts explaining to them how they'll have to partecipate in all sorts of games for whatever reason (it all seemed like a tv show of sorts). The protagonist (a guy) makes friends with a girl first, and then with time increases the allies I believe.

One of the misteries was that the protagonist had like a twin brother, that he doesn't know where he went or what he's up to. Or maybe he even forgot he had one. I'm not sure. But towards the middle of the story they finally meet, and I remember there being a weird swift in the story, which is why I stopped reading lol I wasn't really getting what was going on.

I sadly don't even remember if there were superpowers or stuff like that. But I think they were mostly ordinary people trying to solve riddles and sometimes collaborate against other groups in battles and such. Which made me more confused I believe, because when the brother appears, it happens while there's some kind of zombie type level going on?? Again, at one point things got very confused..

I'm itching to know how things developed from there.. so I wanted to try and read it again. Help me find it please!