I'm looking for a specific Japanese death game manga. It's been a few years so my memory might be spotty. Warning, some of the themes I remember was that it was very violent and sexually explicit.

The manga starts with the protagonist, a male teenager, waking up in a large room with a number of unknown people, atleast dozens or a hundred. The people vary in ages and gender from teenagers to older adults. Some people know each other. One of the people he recognizes is his female classmate. I think there is some kind of an announcer telling the contestants their experience is being broadcasted to the rich and powerful for fun. Then the room begins to fill up with water. People struggle to survive and turn on each other. Then one of the other contestants - tall, muscular yakuza-like adult radiating power and violence- makes some kind of deal for protection with the female classmate. It's implied to be for sex but it's unclear later on if he actually forces her or not leading to him being a sort of morally-gray character, as in not a good guy but not irredeemably evil compared to the villains behind the death game. The surviving contestants manage to escape by figuring out the puzzle related to a statue head where the water was coming out of.

The protagonist seems to be an intelligent individual and is usually the first to solve the puzzles. Although the tall adult isn't stupid, his physical abilities stand out more to a shocking degree.

Later on there's some kind of suspended tram event where I believe the survivors are attacked by ape-like creatures. The enemies look like animals but they are able to use tools like spears and I'm not sure, but I think they use explosives.

Further into the manga, the enemies the survivors face become even more fantastical - as in supernatural prowess and regenerating limbs. Some creatures are outright monstrous in appearance, though the most dangerous seem to be their human opponents who are both frighteningly cunning, cruel, and physically powerful.

In fact the tall adult from earlier loses his arm but he eventually wakes up with a new one. I think it's implied that the contestants' bodies have changed and they have attained supernatural abilities somehow too, though in comparison to their enemies, the contestants' abilities seem somewhat weaker.

There's another gyaru-like character who seems to be part of the main cast. She has been there for most of the story. She seems like a relatively strong-willed character. Despite facing sexual harassment from their enemies, she doesn't allow herself to break down and fights back allowing her to survive.

The setting seems massive. At the beginning it seemed like they were simply in a large building but as the contestants traverse the story they enter different biomes with a sky, and it almost seems like a different world, though it's implied to be a controlled environment not some isekai experience. And although there are supernatural abilities I don't recall them being portrayed as fantasy magic. The beginning of the manga shows a modern society implying some other source for the supernatural factors. At the time I read it, I wasn't sure of the circumstances because much of it was untranslated.

This definitely sounds familiar but I can't put a name to it. I hope someone comes through soon.

I am also hoping someone figures this out

Haven't read it in a couple of years so I cant really remember the details but could it be 100-man no Inochi no Ue ni Ore wa Tatte Iru?

~4400 manga completed
~1700 ongoing...