1.0 WARNING
Don’t: 

• play online with random people while having this mod, play it only with friends, since playing with modded stat can result in a cheat report. 
  

• USE TRAPS UNLESS TO CAPTURE MONSTERS, SINCE SPAMMING TRAPS MAKES THE MOD BASICALLY USELESS.
  

• USE ANY OF THE FAST LEVEL UP GEAR THEY GIVE YOU. It totally gives you an unfair advantage.
  

General Advices: 

• Read all the content below to see all the changes
  

1.1 Stat Changes
The mod realism mainly focuses on monster output and received damage by players or other monsters. 
The monster output damage is set to a rough 65%+ (currently working in low and high rank) while the defence parameter is set to 165% (meaning that you deal almost 65%+ the damage) , both for small and big monsters. 
This mod is intended for veterans, since the higher monster damage output makes the game significantly more challenging for newbies, while maintaining the gameplay fair for the player. 
Even low rank monsters are now more of a threat, making them more fearsome and challenging.

Higher damage output changes the game mood to a more strategic approach, simulating more an actual hunt where you need to prepare yourself differently for each monster, especially for higher rank folks, focusing on defence and elemental resistance more than just damage skills. 
Also the gameplay flow is more dynamic, always keeping the adrenaline up, especially when the monster goes bananas.

Defence stat not only changes the amount of damage a monster can sustain before getting killed, but also changes the body part HP, the status and elemental buildup\resistance and stun, fatigue, rage parameters.
As you can see the game awards the player when trying to get an upper hand on the foe, but be aware, also the monster will fight you back more ferociously!
The mod is basically a glass cannon mod, with high risk high reward moments, where you need to fairly know your enemies before going on a hunt. 

The Mounting is more difficult to achieve but rewards way more the player allowing more damage output. 

1.2 Custom Missions 
Some of the quests (especially the arena ones) have been tuned up to be more of a challenge, emulating MHGU style, with big areas and many monsters fighting each other , in order to make use of the enhanced monster turfs. 

1.3 Arch-tempered custom missions
From HR Arena missions you will encounter Arch-tempered Monsters, but be aware that they DON’T drop anything more than their normal counterpart, they’re a challenge but for editor limitations they can’t drop anything new.

1.4 Monster Interaction and Turf Wars
Monsters battling with each other is a new feature added in Monster Hunter World, making them seem more alive and natural.
Sadly normally in the game the monsters don’t give much of a threat to each other, dealing poor damage quantities to each other. 
Now the monsters aren’t annoying while fighting each other, but they’re useful, and they actually damage each other!
Turf wars are especially modified by it, so let the match begin!! 

1.5 Unavailable or unmodded quests and missions 
Investigations, aren’t modded, since they don’t have a quest ID
Same goes for the guiding lands.
Also carry missions and carve missions haven’t been modded.

Some event quests are modded, see the label at the end of the document   

MR Event monsters can’t be modded (excluding Alatreon) 

1.6 Weapons
Each weapon now behaves slightly differently, since the gameplay flow changes also you have to adapt to this new rhythm.  
For example the bow now is more useful when spamming than with charged shots. 
Obviously the behaviour change varies from player to player.

1.7 Online
The online is ok, both of you need to have the modded files before playing. DO NOT INVITE RANDOM PEOPLE, JUST PLAY WITH FRIENDS SINCE YOU CAN BE REPORTED FOR CHEATING. 

Multiplayer Modifier was set to all LR and HR missions to a minimum of 10, while MR missions are set to a minimum of 120 

1.8 Modded Special and Event Quest
In the images there's a label of every modded event quest apart from principals and optional.