It was kinda always needed to fix a few small things but is now more necessary to see new content.

Patch 4 introduces:

• Two new factions with new missions and events related to the factions
  
• New enemies specific to new mission types and quests
  
• Dozens of new items purchasable with faction reputation
  
• New backpacks from each faction to go with their existing outfits/armor
  
• A new small submarine turret
  
• A new batch of somewhat powerful genetics unique to a specific new gene splicer
  
• A new affliction tied to various new medical items and drugs
  
• Overhaul to submarine upgrades with new upgrades, changes to cost and stats
  
• Some minor fixes and changes to a few things

The main focus of the update is expanding on the rewards of faction reputation by adding new weapons and items tied to each faction, as well as adding two entirely new factions. I have done my best to make these factions fitting for the setting of the game (especially since one of them has already been mentioned in game). They both have unique faction identities, rewards, motivations, and characters to meet. They have lore documents you can read to understand their motivations, they have companions to recruit, missions and events for reputation, just like Husk and Clowns but they have a lower max reputation as they show up a bit less frequently (to not detract from clowns and husks too much).

In addition I have been busy making a lot of new items, new medicines, genetics, weapons, and even a submarine turret. All of the factions also have "unique" faction weapons as a reward for nearing maximum reputation. Most factions also offer a blueprint to craft faction weapons once you reach near maximum reputation. There's a new resource and affliction to capitalize on with cell matter and genetic instability. There are new mutations with powerful effects in the form of genetic mutagens. There are also plenty of small changes, balancing tweaks, and even a few little secrets like I add in every update. This is one of the biggest and most ambitious updates I've done since the release of the mod, so I hope everyone likes it.

That's the main focus of the update but you can find more details and items added in the spoiler tab below.

• Anti-Material Rifle: A powerful rifle that does a tremendous amount of damage, especially to structures. Uses a new ammo type of Anti-Material Rifle Magazines.
  
• Twin-Linked HMG: A slower firing slightly more accurate pair of connected HMGs, for a more precise heavy hitting variant.
  
• Assault Pistol: A "pistol" that uses assault rifle magazines and fires somewhat quickly. A dependable firearm. (Does not count as a pistol for talents because of its use of assault rifle ammo and coding restraints)
  
• Tactical Backpack: A backpack that can six slots of ammunition and two slots of small or medium weaponry. Does not slow the wearer.
  
• UNIQUE Gauss Anti-Material Rifle: A variant of the Anti-Material Rifle with its own ammo type. It does less damage per hit, but it capable of piercing an unparalleled amount of targets for devastating effect.

• Rivet Machine Gun: A lightweight machine pistol that fires rivets from a box of rivets with the help of a welding tank, for very high armor penetration and fire rate, but low damage. Holds a lot of rivets.
  
• Compact Assault Rifle: A less accurate and faster firing variant of the Assault Rifle which can be stored in your inventory instead of needing to be stored on the back.
  
• Revolver Carbine: An older alternative to the handcannon, a carbine rifle with a revolving cylinder that uses handcannon ammo to provide more damage at the cost of fire rate over the standard handcannon.
  
• Runner's Backpack: A backpack with 9 small item slots and no movement speed penalty
  
• UNIQUE PDW: A small suppressed machine pistol that fires very quickly and uses incendiary ammo for very lethal damage per second.

• Light Wrench: A modified heavy wrench that acts as a toy hammer and harmlessly bonks people.
  
• Vanishing Actpack: A duffle bag that functions like a standard backpack, but allows for players to climb inside like a clown crate.
  
• One-Man Bandpack: A backpack that plays amazing clown music to run around and annoy inspire your friends
  
• UNIQUE Clownshot: A one-handed handcannon that plays wacky sound effects and shoots confetti. Does less damage than a standard handcannon but can be dual-wielded.

• Zealot's Zweihander: A large two-handed sword. Pretty standard decent melee weapon, though it may hit walls a lot in submarines due to its size.
  
• Thanatos: A 13 slot backpack with slightly slower movement speed penalty. Allows players to climb inside like a clown crate.
  
• Pharos: A giant lantern backpack that can be powered with batteries, or can be powered with a husk lantern to act as a husk lantern amplifier.
  
• UNIQUE Husked Bone Scythe: A scythe made from a moloch bone covered in protruding husk stingers, to impale targets gruesomely.

• Healing Rifle: Similar to the restoration rifle but heals as long as your beam is touching the target, not a persistent heal over time buff. Gives Genetic Instability with overuse. Uses Healing Cells as ammo.
  
• Gauss DMR: A DMR that fires electromagnetic slugs and requires a battery, but has no charge up.
  
• Plasma Sword: A one-handed melee weapon that requires a battery. Deals high structure damage and moderate burn damage. Will not work without a battery, and the battery will run out of power over time, as well as when you hit anything.
  
• Rapid-Recovery Serum: A drug that can sit dormant in your system until you take damage, causing you to rapidly recover from the damage and proportionally consume the buff. Does decay over time, and will give you opiate addiction, overdose, and genetic instability if overused.
  
• Institute Gene Splicer: A gene splicer with a slot for one genetic material and another slot of a genetic mutagen. Mutagens are listed lower in the post.
  
• Institute Doctor's Fatigues: An improved version of medic fatigues with one more inventory slot and slightly improved protection.
  
• Institute Research Diving Suit: An abyss suit modified to have improved audio quality, and protection from elements such as radiation, burns, acid, husk infection or bite wounds, but low protection from any other damage types.
  
• Sample Collection Pack: A backpack with no movement speed penalty, nine inventory slots and one slot specifically for carrying alien artifacts and nullifying their effects.
  
• Gene Stabilizer: A medication that can cure Genetic Instability. Can be crafted without recipe as well using Cell Matter and Stabilozine.
  
• Healing Grenades: Both the 40mm and standard handgrenade healing grenades, which provide a quick burst of healing gases, but can also cause lapses in consciousness and opiate addiction with overuse.
  
• UNIQUE Flaming Power Sword: A two-handed version of the Plasma Sword, but instead of destroying structures, it can repair hulls it hits. Can also light people it hits on fire.

• Mini-Spine Pistol: A one-handed pistol that shoots steel or spineling minispines. Requires an oxygen tank, and can be dual-wielded.
  
• Thresher Bone Knife: A knife made from the jawbone of a bone thresher, which can inflict bite wounds and infected wounds.
  
• Mantis Gauntlet: A severed mantis claw attached with a handle so you can swing and punch with them, to poison targets with paralyzant and knock them out.
  
• Mudraptor Shellmet: The head piece of a mudraptor's shell, which can be worn as a cheap but effective helmet.
  
• Mudraptor Veteran Armor/Shellmet: Improved mudraptor armor and shellmet.
  
• Shellsuit: An abyss dive suit with improved physical damage resistance.
  
• Chitanium Armor/Helmet: Armor made from titanium and chitin that provides excellent protection.
  
• Jump-Start: A powerful chem that can quickly heal most ailments and get someone on their feet. Does not require high medical skill to be successful in saving someone's life, but does require high medical skill to minimize the ensuing chem addiction and genetic instability. Should not be overused because the side effects are dangerous, but great for saving a life in an emergency.
  
• Thresher Oil: A cheap booze that will get mess you up. It is purported to be a cheap medicine and have healing properties, but the effects of the alcohol are inconsistent. It is likely to give you hallucinations and psychosis in addition to getting you drunk.
  
• Gene & Tonic: An alcoholic drink combined with alien genetic material. Gives you genetic instability resistance when consumed, but if used to clean infected wounds, can give you genetic instability when used on the skin.
  
• Abhuman Outcast Attire: Clothing made from crawler hide that offers more protection than most clothes.
  
• Crawler Pack: A backpack made from the taxidermy corpse of a crawler, which can carry eight small items and slightly increases swim speed.
  
• UNIQUE Oblongata: A "grenade launcher" made from thalamus flesh that fires dormant terminal cells which stick to things, burn them with corrosive acid and then explode.

This cannon is like a flak cannon without the flak. It fires explosives that burst just before hitting targets which decreases your chance of missing, but may also do a bit less damage than a direct hitting explosive. The ammo types are as follows:

• Standard Ammo: Explodes in proximity to enemies.
  
• High Explosive Ammo: Has a larger explosive radius and more damage.
  
• Depleted Fuel: Has increased armor penetration (if it does direct hit) and deals radiation damage.
  
• Physicorium: Has no proximity detonation but has high damage on impact and armor penetration.
  
• Armor-Piercing Incendiary: Has increased armor penetration (if it does direct hit) and deals a large amount of burn damage as well as explosive damage.
  
• Fulgurium: Creates a chain-lightning effect which can stun and incapacitate enemies near the point of detonation.
  
• Acidic: Leaves a cloud of acid upon exploding which deals damage over time.
  
• Gravity: The same as gravity railgun shells or flak ammo, but shorter and faster.

• Crawler: Gives thermal vision
  
• Mudraptor: Gives 20% movement speed and 20% melee attack speed
  
• Thresher: Gives pressure immunity
  
• Spineling: Gives 50% ranged spread reduction
  
• Mantis: Gives poison immunity
  
• Moloch: Gives 50% explosive damage resistance
  
• Hammerhead: Double plasma cutter structure damage and mining speed
  
• Hammerhead Matriarch: Gives 20% increased maximum health
  
• Crawler Broodmother: Gives nausea immunity
  
  Also adds one new genetic material obtainable like any other genetic material:
  
  
• Crawler Broodmother Genes: Gives up to 100% increased buff duration.

Submarine upgrades have been tweaked. Now every upgrade is similar to hulls, in that every upgrade has six levels, with two levels available per level of submarine. Every upgrade also now has a material cost of three of some resource, with each upgrade taking different resources to make more resources useful and give you a resource sink as well as a money sink for progression. In total, when fully upgraded submarines should be slightly stronger than before, but will also cost more money and resources which is the goal. Also, more upgrade bonuses have been assigned to the different submarine types, so the submarine type is a little more impactful with what bonus upgrades they can get (two more levels in 7-8 different upgrades).

• Added two new factions
  
• Added two new companions with quests
  
• Added a number of new events related to new factions
  
• Added a variety of vanilla items to faction merchants
  
• Added new enemies which show up in new mission types
  
• Added a new non-explosive 20mm autocannon ammo type
  
• Reworked/Fixed some Medic Talents
  
• Probably more small tweaks and fixes, but I forget

If I remember any more changes I will try to update the patch notes, but I did a lot over the span of the last month or so, so I can't remember everything and I have misplaced some of my notes on what the update contained so I had to try from memory. My memory is terrible. This update may be contentious with the changes to submarine upgrades and the addition of new factions, but I really hope people enjoy it.