Description
WARNING: This mod contains spoilers for Stranger Things. Please support the official show on Netflix!
Welcome to Prim's Stranger Things Mod!
The Upside Down
"It's like home... But it's so dark and empty, and it's cold!" -Will Byers
A dark reflection of our world, the Upside Down is always there, you just can't see it. It's dark, covered in tendrils, filled with spores and choked with an omnipresent fog. It looks just like the home you're familiar with, but no human traces can be found. Except... traces of redstone from the other side may bleed through, allowing contact with home...
Getting to the Upside Down.
Reaching the Upside Down requires a gate between dimensions. These can be hard to find normally, however. A gate would require so much energy, it may disrupt the magnetic field! Grab yourself a compass and it will point toward the nearest gate. Follow it! It should be hard to miss.


Once you find a gate, you will have to push through the gross membrane to get in!
Welcome to other side...

The Upside Down is a rather eerie place. No one is here, no mobs, no animals, no people (besides you). You are free to explore as you please. Though everything you know from back home is here. Including chest items. There are strange vines over everything that wrap around blocks and seem to grow when you aren't looking... But, the Demogoron is always on the prowl. It will be searching for you and will attack at a random time between 2-5 Minutes.
The Redstone System
If you've seen Stranger Things, you may recall Will Byers (and later Nancy Wheeler, Eddie Munson, Robin Buckley and Steve Harrington) communicating with our world through the lights. This feature is present here! Your presence in the Upside Down will interfere with redstone back home. Causing it to activate when you're near.


The World Mirroring System:
The Upside Down is a mirror of the overworld, as such. It will copy all of your builds and the like over. When you first enter the gate (or use /initializeUpsideDown true), the game will load all player visited chunks into the Upside Down. Even removing water, lights and leaves! Keep in mind, the Upside Down is programmed to generate as a perfect copy of your world's seed, so if you leave the area you built in, you should still see new chunks being generated that fit the world. (Unless you use Season 5 generation, which is a gamerule.)
Consider:
The Upside Down only initializes once, when you first enter. So any new builds you make in the Overworld or Upside Down will not reflect. Unless you type the command: /initializeUpsideDown true. This command will re-initialize the Upside Down. Though this will erase all old chunks in the Upside Down. Removing anything in there that isn't in the Overworld.
The Monster:

"A monster... from America." -Dimitri Antonov
The Demogorgon is the current primary predator of the Upside Down. It is ferocious and strong, able to kill an ill-equipped human in seconds. It smells blood, if you happen to cut yourself, you may be in for a nasty surprise when it gets dark. If you aren't careful, you could end up it's next meal. Though, it doesn't like fire. So bring a match if you plan to fight this monster... Be careful, the Demogorgon is part of a hive mind. If you step on a vine for too long, it may alert the creature to your location. Shearing off a vine or using fire to chase them away is a good countermeasure. But if the monster sees you, it will pursue you relentlessly unless you distract it.
Future Plans:
This mod will be released in five major content updates, one for each season of the show. Each update will try to rework that season's ideas into a cohesive survival horror experience. While I want this mod to follow it's own artistic vision for features, asthetic and overall gameplay. I am not above changing my plans or adding fanservice for people who want it. No shame in a little fun, right? Each update is indicated by the first digit of it's update number, it works like this:
(Number of major update).(Number of small update).(Number of patch)
So a small patch for update 3.0 would be 3.0.1. But if I added something significant that will become update 3.1.0.
The updates:
Update Zero: (Released)
-Adds the Upside Down dimension.
-Adds a mothergate structure that allows access to the Upside Down.
-Adds a comprehensive system for importing and processing overworld chunks to the Upside Down allowing for build mirroring.
-Changes compasses to point at the mothergate.
-Adds some random trees with gates in them to access the Upside Down.
Update One: Close Encounters with the Other Side (Released):
-Adds the Demogorgon that can kidnap you to the Upside Down and hunts you mercilessly.
-Adds the bleeding effect that alerts the Demogorgon.
-Adds the Upside Down's vines effecting the hive mind to alert the Demogoron.
-Adds gates the Demogorgon makes on the ground to traverse the dimensions.
-Adds a flashlight to see in the Upside Down.
-Adds redstone being effected by player presence in the Upside Down.
-Adds block culling to syncing, making the Upside Down remove lights, water and leaves seamlessly.
-Adds "no sync" mode where the Upside Down generates off a duplicate of the world seed and doesn't import chunks. (Gamerule)
-Adds "Season Five Generation" mode where the Upside Down will forcefully generate a 51x51 area or more as the only areas you can explore with the rest being blocked by a giant wall and a roof that resembles the Abyss.
-Adds optional support for Immersive Portals where the player must break through the portal membrane to open it.
Update Two: Invasion of the Demodogs (Yet to be released)
-Adds the Mind Flayer as the overarching antagonist that watches you and acts as the brain of the Upside Down.
-Adds Demodogs, adolescent Demogorgons that act as an invasion force to enter your world.
-Adds three opinion states the Mind Flayer can feel for you. THREAT which makes the Mind Flayer more likely to send hordes after you to try to kill you. VICTIM which makes the Mind Flayer take more of an interest in adding you to it's hive mind. And USEFUL which is for future stuff.
-Adds Mind Flayer awareness where the Mind Flayer can only mount attacks on players if it knows where they are. Being spotted by a flayed entity or stepping on a vine will cause the Mind Flayer to know where you are.
-Adds the "Flayed". A system where players or mobs can become spies for the Mind Flayer and do it's bidding.
-Adds the ability to save yourself, friends or mobs from being flayed by torturing the Mind Flayer out of them.
-Adds "true sight" where high Victim players will hallucinate the Mind Flayer.
-Adds a bunch of custom skybox animations where the Mind Flayer will menace the player by stalking them in the Upside Down should it be angry enough.
-Adds a tunnel system called the Underdark that dynamically grows under your world from a large cavern below Mothergates.
-Adds "growth points" to tunnels where they begin to spread an infection to your surface and create infected "Upperdark" areas. These can be burned away to cure the area.
-Adds random ambushes by Demodogs that burrow from the tunnels to explore.
-Adds a Eleven's telekinetic powers with custom mechanics and combos to add a new dimension (not a literal one) to fighting.
-Adds telekinetic struggles where players fight with their minds.
-Adds Molotov Cocktails and Soul Molotov Cocktails to light the fire up in the Upside Down.
-Adds a second massive entrance to the Mothergate that acts as the source of the the blight on your world.
-Adds a minigame to seal the gate and destroy the blight on an area.
-Adds a brand new, original passive Upside Down originated creature known as a Flumph that just wants to be your friend! (And snitch on you...)
-Adds Demogorgon life stages and molting/growing behavior.
-Adds the ability to raise a Demo from infancy and domesticate it as your new best friend!
-Adds a decay system where overworld tools will become less effective in the Upside Down.
-Adds new makeshift weapons that can be crafted from bits and bobs in the Upside Down that do not decay. They're powerful but break faster, but are easy to repair.
-Adds Upside Down sickness where prolonged exposure to the atmosphere can be bad for your health.
-Adds slug "impregnation" where the Demogorgons use your live body to incubate it's young. (ew)
-Adds the Abyss that can be accessed by reaching the Upside Down's roof in Season 5 generation mode. Note this is just for fanservice and is a prototype so it will be pretty empty in this release.
Update Three: Night of the Living Flesh (Upcoming, plans still unconfirmed)
-Adds the Mind Flayer melting down creatures once it becomes angry enough at the player.
-Adds Meat Avatars the Mind Flayer will use sometimes in emergencies.
-Adds the mod's final boss, The Meat Flayer. A grotesque giant flesh avatar that will try to kill you or steal your powers if you have any.
-May add more custom mobs like the Thessalhydra/Tunnel Queen and some custom flesh monsters.
Update Four - Nightmare on the Block (Upcoming, plans still unconfirmed)
-Adds Demobats.
-Adds Demospiders (that will likely be configurable if you have arachnophobia.)
-Adds expanded Upside Down flora and fauna.
-Adds expanded psychic powers like mutations, ability strength, power granting and new powers.
-Adds the ability to ally with the Mind Flayer and become a "Litch". (Vecna)
-Adds the ability to enter the Void with Remote Viewing and stalk your friends or mobs.
-Adds Camazotz, a place where victims of Vecna are trapped during hallucinations.
-Adds the ability to curse players as Vecna and psychologically torture them until you use your powers to crush them and open a curse gate.
-Adds "Four Chimes" disaster where four curse gates merge and create a massive rift that decays at your world.
Update Five - The Flayed Crystal (Upcoming, plans still unconfirmed)
-Adds a proper flesh wall to the Upside Down.
-Adds a final dungeon to the Upside Down roof to properly unlock Eleven's powers. (Note you can get the powers in survival even in Update Two, but this would be the intended survival mechanic.)
-Adds "Sorcerer" (Will's) powers unlocked after being saved from being flayed.
-Adds some more custom creatures.
MISC - Things that may just be added whenever
Suggestions for update mechanics can be sent in the suggestions channel on the Primrose Studios discord. If I think your idea fits, I will work it in.
New original creatures. I want to expand on the Upside Down's lore and worldbuilding to make it an actually compelling place to visit and make the danger of it worth it.
Biome specific fauna to the Upside Down.
"The Cult of the Arthrodomius" as a villainous cult of illagers and villagers who were trapped inside the Upside Down long ago and now worship the Mind Flayer as a god.
Any new ideas that are suggested by the team or players for lore and worldbuilding. (This mod's lore doesn't stricly adhere to Stranger Things and is going in it's own direction to maintain a cosmic horror vibe.)
A horde bossfight gamemode set in the Abyss with a custom final boss of the "Abyss" Mind Flayer spider form and Vecna. (For fanservice, I love y'all too much)
Bikes! Some form of "rustic" hand-build bike would be cool and... you don't got Stranger Things without bikes.
Stuff I really don't wanna add:
Modern technology likes guns, flamethrowers or anything of the sort. This mod is asthetically based on a Vanilla+ style. So I'm sticking with low-tech stuff like Molotovs or Redstone. The ONLY exception is the flashlight, but I tried to make that feel like it's still redstone.
NPCs of the characters. I still don't get why people want this... Do you just want Steve "the hair" Harrington to just randomly spawn in a forest somewhere?
An NPC Vecna (outside of the final boss version for Horde Mode), Vecna is such a personal antagonist that I don't think I can do him much justice unless you play as him.
New ores, just no need for them. New resources from the Upside Down will have different functions.
An update related to Tales from 85. This is more of a maybe. I MAY include stuff from the show that fits the mod. But I don't think a comprehensive "Update Eighty-Five" or whatever will happen unless the show ends up being literally the coolest thing ever and everything it adds is cool that I literally cry from sheer peak.
The Abyss crashing to the Upside Down, this feels too permamnent of a thing to add as people will want a way to reverse it. I may add some way to lower the roof to simulate it.
Destroying the Upside Down, while I may add some kind of comsmetic Exotic Matter thing. A full way to destroy it is kind of counterintuitive to the mod's purpose. If I do add this in any form, it would be a fanservce thing and not a proper mechanic.
A proper forge port, just use a connector bro. Future is now old man.
A bedrock port. Code wise, Bedrock is a completly different game from Java and I don't understamd how it works. I also don't care enough to bother.
Frequent version updates. Mojang keeps changing massive parts of Minecraft's code. If I was to keep updating the mod for new versions, I'd basically have to maintain multiple entire versions EVERY SINGLE time I want to update. I am one lady, I do not have the time for that.
KNOWN ISSUES:
-The Upside Down is NOT compatible with any world generation mod that alters the world height, removes features, adds features or adds modded blocks. The Upside Down generates based on the basic world seed and cannot read mods. This can be fixed by using Season 5 mode since in that mode, the Upside Down is ONLY synced chunks which do copy modded stuff properly. Note that the world height of the Upside Down is fixed so mods/packs that change that will likely not work.
-The Upside Down isn't compatible with shaders, use them if you wish. But they will break the intended effects. You can always modify them I guess, but I still don't reccomend it.
-The Upside Down doesn't work well with Distant Horizons due to DH removing the fog that makes the Upside Down so creepy.
-If you play an old world, you need to run it through the "optimize world" function Minecraft has or it wont sync properly.
-Mothergate sometimes spawns weird, this is a product of Minecraft's generation engine.
-Performance can be a bit wonky. I will do what I can to fix it where I can.
COMPATABILITIES:
-Immersive Portals has official support but is not required. There are even some exclusive immersive features added when you use it.
-Sodium, should be a given but there have been issues with this before. Also not required.
-Sinytra and Kilt connectors both work fine. Allowing crossplay between Forge and Fabric.
-World gen mods (when you're using S5 mode).
-Dynamic Trees. (You'll need a connector for it, but it's super cool please try it.)
-Custom maps can be synced into the Upside Down with the command /initializeUpsideDown.
CREDITS AND SPECIAL THANKS:
(Most) 2D art assets by Unvalid.
3D assets, animations and sound design by Noelle.obj.
Inspiration for the vines implementation came from Beardielover's "Stranger Things Experience Mod".
Loananas for the Demogorgon's body model and texture.
Xcft for the bleeding effect's texture.
TheDoGGyS for the main menu logo.
.ganymedes__ for the floor gate's model.
N ess for the mothergate's model.
Special thanks to Netflix, Stranger Things and the Duffer Bros for creating an amazing show and inspiring this project. It wouldn't be possible without them!
And you, for considering playing my silly little project.
Want to connect with me or other players of the mod? Join our Discord!
This mod is being made by one amateur programmer and some help from friends, I can use all the help I can get. So if anyone wants to contribute programming help, animations or models, textures or anything at all. Please contact me on Discord through the server!



