Green Hell

For those wondering how different this game is from the forest, here's a perspective from someone who owns both games.
The main difference is that green hell isn't a power fantasy like the forest. In the forest you can blow up mutants and cannibals with molotovs and bombs. Or use fire arrows or flares to light enemies on fire. You can also upgrade you weapons with stuff like human teeth and bird feathers to give them a stat buff. Green hell is less combat focused. You get different tiers of tools and weapons, with stone being basic tier and metal being the best tier. That's about it, you can't blow up jaguars or natives with bombs or light them up with flares.
Green hell does have tribal native people, but they are much less of a nuisance. They don't spawn often and even if they do, they won't send waves of tribals near your location. They spawn, and if they spot you and you kill them all, it won't escalate any further like things do in the forest. There are only two main types of tribal people, archers and spearmen, no Virginia mutants or cave mutants. Again, it's less focused on combat.
Enemies in the forest are all human based. In green hell, there's more variety, you get jaguars, mountain lions, caiman and other hostile animals. And these animals don't fuck around and an unprepared encounter can easily spell death. A leaf bandage will do fine against scratches but it won't do anything against a deep jaguar laceration. It depends on if you have the knowledge to treat the laceration, better yet, kill any animals before they can even harm you. That said, it takes knowledge and skill, since you all you have are spears and bow/arrows, no molotovs or bombs.
Food and water is also much deeper in green hell. You have different nutrients such as proteins, fats and carbohydrates, so eating a piece of meat won't replenish your carbohydrates, it's less like the forest where you can likely survive off a single food source. And this mechanic isn't here just for the sake of variety, failing to satisfy any one of these nutrients can lead to reduced health and stamina, which can further affect your ability to survive.
This is a good segue into stamina. Stamina in green hell is also very important, it doesn't just affect your movement and combat. If your stamina and energy fall too low, you'll pass out on the spot. This will then lead to parasitic worms living underneath your skin, rapidly draining your sanity, which if left untreated can spell another death. So to stop yourself from passing out and getting worms, you need to sleep regularly on a bed. Stamina also dictates if you can light a fire, unlike the forest, you don't have a Bic lighter with infinite fuel, you need to start a fire with a drill firestarter, which uses a substantial amount of stamina and energy. If you don't have a fire, you can't purify and boil water, or cook any raw meat you have. Foods in green hell expire quickly if you don't cook or eat them.
Next is the sound design. Green hell's sound design doesn't just sound good, it is also very very crucial to survival. In the jungle, there's an overgrowth of bushes and trees, so it's very easy to miss any threats that are around you, such as rattlesnakes, giant ass spiders, tribal people and Jaguars. The only reliable way to identify these threats is by the distinct sound in which they make. Hear a snake rattling? Stop moving any closer and go around the source of the sound. Hear the low growl of a jaguar inching closer? Get ready for an encounter. Hear the singing of tribal people? Crouch down and avoid alerting them. Because more times than not, you won't be able to see these threats. In the forest, you can turn off sound completely and still stay alive, but in green hell, turning off sound will get yourself killed by various threats.
Lastly, I want to talk about difficulty. So far I've built up green hell to be this hardcore survival game, whether it is 100% realistic or not is still debatable with sometimes questionable AI patterns, but in its core, green hell is a hardcore survival game. That said, it's actually very customizable in its difficulty. Don't want to get bit by snakes and spiders? You can actually turn it off, don't want to deal with tribal people? You can turn it off as well. Don't want to deal with sanity, there's another option for that as well. It's much more customizable than the forest. You can go in blind and get killed over and over again. But like any hardcore game, it can be very rewarding. If you want to challenge yourself or just want to play like an Amazonian tourist, you can customize the difficulty to your own liking.

Start with nothing and no idea how to survive. Die a few times, and figure out the basics: you can eat this, you can't drink that. Die a few more times from parasites or disease, and discover which plants have medicinal properties (and pay for that knowledge with poisoning or death a few times). Survive longer, build weapons, defend yourself from enemies and predators.
Eventually, you know every food and water source, can crush every enemy, can build anything you need. You are more than a match for anything this inhospitable world might throw at you. Nature regards you with awe: you are the King of the Jungle.
Then step on a scorpion far from your camp. Your bandages with antivenom herbs are back at camp. Stumble around looking for the herb you need. Your fever rises.
Pass out on the forest floor. Wake up: parasitic worms hiding in the muddy ground have made a home under your skin. Use a bone fragment as a needle and dig them out. Pass out from the pain.
You wake up dangerously dehydrated, and your makeshift coconut canteen already drained. Making it home is your only hope. You start in the right direction, but the combination of the fever, the now infected scorpion sting, and the open sores from your impromptu worm surgery have weakened you so that you can only make it a few hundred yards in between passing out.
Your periodic unconsciousness gives more worms the opportunity to claim a new home. The fever rises. Dehydration worsens. Hunger racks your body. You hope the growl you heard was just a mouse, and not a jaguar hunting you. Irrelevant, as you pass out again.
You can make it, less than a mile to go. Medicine, food, water, fire, and rest all await you. Just a little further.
You stumble one last time, and fall to the ground. This time, you don't rise again. Throat parched, delirious with fever, body covered in wounds and sores. Your vision fades to black.
Scavengers consume your body, and the sun bleaches your bones. Nature looks with indifference over the few scattered, splintered bones that mark your final resting place.
Here lies the King.

Day 1: Stepped on a venomous snake and died.
Day 2: Ate a poisonous mushroom, got food poisoning and died.
Day 3: Fell asleep on the ground and got worms.
Day 4: Got mauled by a jaguar and died.
Day 5: Did Ayahuasca and got lost in the jungle.
Day 6: Met the locals, took an arrow in the knee and died.
Day 7: Found a drug lab... I think I'm going to like this game.
Edited: Spelling mistake.

Day 1: After falling off of a cliff my bf and I start our wonderful journey into the jungle, we run into some naked dudes
We Die.
Day 2: We find a cliffside to build a small camp on, we sleep in our cozy new tents.
My bf gets worms and dies.
Day 3: We try to find water. We don't know how to make fresh water. I drink from the river.
I get parasites and die.
Day 4: We begin to build our base. My bf hears a growl in the distance.
We get mauled by a jaguar and die.
Day 6: My bf starts to hallucinate, he begins to laugh uncontrollably even though the game is not making his character laugh. I am scared. This game is terrorizing us irl. He sees a naked man running toward him.
He dies.
Day 7: After a quick glance at the wiki we finally understand how to drink clean water. I pick up an alive poison dart frog.
Immediately dead.
Day 8: We drink ayahuasca. I finally understand what it is like to feel high. After I'm done hallucinating we run into the new open woods.
I run into a jaguar and die.
Day 9: We run into an illegal gold mine and try to understand spanish.
I am dying internally.
Day 15: We run into an illegal drug factory and read sad love letters.
I am crying inside.
Day 20: We find a plane. I realize that the main character is an awful person.
Day 21: We get to the end of the game. We get the wrong ending. I feel like shit.
I die to the naked man.

The first 15 minutes of this game teaches you one very important thing: Your guy is made of wet tissue paper, and has no place being anywhere outside of a padded cell.
Jokes aside, this survival game is harder than hard. The smallest slip can result in fatal injuries. My guy fell 5ft, got a scratch, which got infected, and died from fever/dehydration/major organ failure. No idea why he even tries to leave the house with how fragile he is, much less venture into the brutal Amazonian jungle where everything with a pulse wants to sign your obituary.
Still, once you get the hang of surviving past your first 15 minutes, things start to get better. There's building, (a bit of) farming, cooking, hunting, fishing, killing tribals, eating them, etc, etc. All of that, while maintaining your macronutrients, something you never did irl... wasn't this praised for being realistic??
If you ever want to feel the stress of metaphorically straightening a crumpled, wet tissue paper without tearing it, try this game.

running around naked, screaming and bashing people with a stick is the best way to spend my day. then i play green hell and get to do it again.

Decent survival game all around but it's not tuned well - you spend upwards of 80% of your time just maintaining not one, not two, but three different food categories (carbs / fats / proteins), which deplete enormously fast. It's gone even beyond 'realism' and requires you to eat much more than an actual human does day to day (I'm on day 5 and I've probably eaten like 40,000 calories worth of stuff... a full crocodile lasted all of one day, when in reality it'd feed a village for a week).