LongTurn Experimental ruleset

LTX as of end of 2022
Ships no longer cause unhappiness when out. The purpose of the ships is to be out on the sea. This is why it doesn't make sense to make the citizens back home unhappy. From the game point of view this makes it more easy to have units on the oceans and the game needs more action for the sea units.
There is a new War Longboat and Ancient Land unit class. War Longboat is for allowing the players to send a low end military presence to areas beyond the deep ocean. Ancient Land unit class is for defining what units are low end enough for that purpose. Warriors belong to Ancient Land units class.
Mass Transit extends the city working area by 20 tiles. Previously mass transit used to extend the city working area by 4 tiles. Now it's extended by 20 tiles. This allows more room for planning the initial settling and creates a choice between placing lots of cities close to each other in the early game vs. having less of them with less than optimal working area before mass transit becomes available.
Air Defense Missile becomes available with flight. 
Two pollution and production reducing wonders. Paris Agreement reduces production by 25% and pollution 40%. The follow up wonder Global Emission Union reduces production by 20% and pollution by 50%. The first wonder affects only some governments and the 2nd one almost all. This makes it possible to use pollution reduction as a weapon or as a tool. This can be countered by building the 2nd wonder. This gives the players more control over how much the world is polluted.
Federation gets 25% sci bonus with corporation. The initial sci bonus of 50% will make federation powerful enough for the early and mid game and the additional 25% with the corporation gives it a boost instead of a massive bonus.
Adjusted unhappiness for conquered cities. No unhappiness for anarchy since there is no system anyway. Communism gets less unhappiness so that it's god for conquering while not that great for research or economy. Federation is supposed to be equally good to democracy and that's why it gets the same penalty for conquering cities. City states has a minor penalty.
SDI I, II and III give 50%,20% and 20% nuke defense. The less expensive Manhattan Project makes the nuclear wars more likely and the SDI I giving a better chance to shoot down the nukes allows most players to balance the threat of nuclear destruction
Manhattan project cost 800 (was 2500), The big nations no longer want or need nukes if it's already possible to win with the production capacity. The smaller nations can't afford spending 2500 to the nukes but they might be able to afford 800. The big nations can't afford making all the cities nuke proof and this may make it a big issue to those who keep big stacks of units in the cities when they attack the smaller nations.
Cities can only be poisoned if they are bigger than size 8. Poisoning cities to size 1 is too powerful and most of the time effectively makes the city irrelevant for the rest of the game. Poisoning to size 8 removes the defensive bonus the cities get at size 9. This way it's still possible to recover and keep the border area cities reasonably relevant. This also allows the smaller nations to have more than a few cities that remain productive.
Hoover Dam costs 700 and gives 2x hydro plant power effect. Hoover Dam doesn't remove as much pollution from other cities as solar plants would do. Only 15% vs. 25%. This leaves room for some improvement. It's also the ultimate power plant building, at least at least for now. With the relatively low cost of 700% it's something the players might want to pursue when researching techs.
Added Small Sea unit class. This is for units that can only travel on water tiles but can also be loaded on other units. Torpedo unit is such unit. It can be loaded on other units but can only move on water tiles.
Advanced Torpedo is a new unit. Advanced Torpedo is able to attack unreachable deep ocean submarines. Bombers and cruisers are able to carry advanced torpedo units.
Nuclear Submarine type II is able to move nuclear units and missiles. Type II is also unreachable and can only be encountered by special torpedo unit the sea units can carry. Or alternatively an another Type II submarine.
Nuclear Submarines are able to carry nuclear units and missiles. 
The first generation submarines are able to move one missile unit but no nuclear units. 
Nuclear units are now on a nuclear unit class. 
Buoys have more vision and the sea units are able to pillage buoys.
Fusion fighter can stay 4 turn on air. 
Cargo Airplanes can move 4 units instead of 2 like on LTT ruleset. The cargo airplanes are one of the final techs in the tech tree and allow the players to move troops with planes. This includes espionage units.
Tribal and Despotism more waste with distance: More waste to distance makes the early expansion more difficult. To compensate there are some new city improvements and effects for this purpose.
The following wonders work as government centers for Tribal and Despotism: Hypogeum, School of Baudhayana sutras, Statue of Zeus and Colossus.
Tech Upkeep will increase with more techs the players get. (1/300 of the cost of the tech)
Tech stealing units have been fixed and are the way for moving techs between the players. This makes the tech trades to have an actual cost. 
Terracotta Army has been introduced as an early Great Wonder. It is a Great Wonder becoming available with construction. It gives the units built in the city one extra veteran level. The players can now choose if they should race for construction to get one city to build v, vv or even vvv units or if it makes more sense to start more early with Sun Tzu's. Being a great wonder it may also make sense to get it for defensive purposes. The enemy can't build it if it's already built. 
Ocean to Swamp transform takes more time. Now creating new land will be more expensive but not yet too expensive for closing strategic locations like for blocking the access for triremes or barges. 
Creating new land on ocean no longer needs adjacent tiles. This change needs to be evaluated at a later time. Needing no adjacent tiles for transforming ocean into swamp allows the players to create artificial islands on the sea if shallow ocean is available. Creating bases on strategic locations makes it much more important to gain naval supremacy and adds another reason for monitoring the activities on the oceans.
Nuclear Plant has a 75% production bonus. In the real world the nuclear plants are really expensive and typically produce lots of power. Nuclear plants have been rarely used since most of the cities already had power plants by the time they became available and less pollution alone wasn't attractive enough. With this change nuclear plants offer an alternative for those who really want to max out the production capacity. Combined with the possibility of meltdown this allows the players to take new types of risks.
Big cities can have 40 units with no food cost. There were only 20 city sizes adding one more food upkeep free unit to the cities. Now there are 40.
New system for getting techs from other players. The actual chance of success depends on the server settings. With a 50% chance the players could transfer max one tech every 2nd turn. No longer instant learning of dozens techs in one turn. With no real cost. Now, all unique, scribe obsoletes with engineers and scholar (available with explosion) obsolete with spies. Inventor is never obsolete (available with espionage)
New building- Workshop - Gives 30% prod bonus for monarchy/republic/city-states. This building allows the middle age empires to compete with those focusing on trade and making gold.
Federation and communism get 25% sci bonus with corporation. This compensates the lack of trade bonus democracy has.
The cities get a size based 10% additional trade bonus with sizes 9, 17 and 30.
Fundamentalism available astronomy with max tax rate at 60%. It's a very good government of one needs to play war and make lots of gold. It however has a hefty penalty on science. 
Stealth is a pre-req for fusion power not labour union
Great library grants 50% bonus to libraries. It's a great wonder and affects all the players. It also gives 10 extra bulbs to the city it's located. 
Trebuchets is a new unit allowing the players to send out slow but really powerful siege units. These units require escort and the fighting often takes place while the units are being moved. It's extremely important for the defender to kill the attacking force before it arrives the target city.
Tech Upkeep (1/300 of the cost of the tech)
It is possible to build cities on glacier tiles.
Cities can be built on Mountains. This allows the players to build truly difficult to conquer cities. 
Nationality meaning that the citizens get angry under a foreign regime, The level of unhappiness defends on the government of the conqueror.
Pollution can appear on ocean tiles. Transports are able to clean it without workers.
New wonder: Port of Guangzhou - Allows v-ships and ships to heal available with construction. This is an alternative to other ports and will not stack up.
The port facility becomes available with metallurgy (was amphibious warfare)
Square Rigged caravel has A2D2 HP12 cost 60 (was A3D2 HP8 cost 55)
Regular caravel has A2D2 (was A1D2)
Damaged ships are not slowed down (trireme and barge are) 
Added new building Academy - Creates v non-mil units.
Sea class units will get +6 extra moves with fusion power tech
Nuclear power gives +3 extra moves to sea class units (was 1)
Unique marine unit available with metallurgy. This Navy troops unit can only be loaded on the unique Flagship Frigate ship.
Alphabet changed to Pictography. Only renaming the tech to illustrate how writing was born.
New L1 tech "folklore", required for Mysticism and Writing.
New Early Wonder - School of Baudhayana sutras gives +4 sci to the city.
New Government City States for those players with very little land. Trade bonus but with a max city limit of 7 with one unhappy for each extra city.
Internet costs 800
Occupation Governement to help deal with nationality. This wonder makes it possible to control the citizens on occupied cities. You will make half of the unhappy citizens (unhappy from occupation) content but will also lose half of the shield and trade production.
There are several scout ships with unlimited range. While the sail ships are able to stay out only for som turns the scout ships can keep con going. The patrol cutter Ship can enter both deep ocean and rivers and becomes available with Engineering. Cog ship can enter both deep ocean and rivers. Becomes available with physics. The prirogue ship is the first of the scout ships and can enter deep ocean, The pirogue becomes available with seafaring.
Jungle gives +2 trade and 40% defense bonus.
Tribal empire sizes; base is 10 and step 10
The square rigged caravel is obsoleted by frigates
Cities have reduced vision meaning that the players may need units for controlling the full working area.
Horsemen obsolete by elephants and not chariots.