Complete list of improvements:
Multiplayer and Matchmaking improvements
Maps are now correctly synchronized when player joins during map loading
Games now filter correctly in lobby
After joining a coop game enemies now spawn correctly
User guidance improved. (Quest guidance, UI, shop)
Additional interface polishing
Map tracking now works correctly after loading checkpoints
Health and stamina bars of enemies now display correctly in coop.
Locations of invisible NPCs are no longer shown
More than one player can now use the same ladder simultaneously
Focus on items in shops is not changing after operation (sell, buy)
Additional Interface polishing
Fixed displaying gather rings near some door
Player death behavior improved
Respawn position now saved when playing in cooperative mode
If player dies whilst inside vehicle, menu will now be hidden
Save game mechanics extended
Added distinction between quest checkpoints and other saves
Minor animation fixes
AI animation now displays correctly after fast travel or travel through portals
AI improvements
Improved enemy awareness (zombies)
Enemies reaction to fire adapted
Enemies are now able to successfully reach player on some arenas
Shooting enemies no longer spawn infinitely
Balancing changes in difficulty, majorly for second playthrough
Item level will be calculated correctly when playing in second playthrough
Kick interrupting reload now adapted, after clip wis inserted reload is treated as successful
Health regeneration is now disabled during grab.
More HP for all escorted NPCs
Removed all instances of Butcher during escorts
Purna can gain bonus rage from both Grim Inspiration and Inspiring Kick
Only "Walker" type enemies increase the extra XP of the "Combo" skill from Xians Survival skill tree
Pause Option added
Added information about players requesting pause (Coop)
Looting rules improved
Thrown items now cannot be picked up by another player for 5 minutes.
Items from just-opened containers cannot be picked up by another player for 5 seconds.
Minor graphical glitches fixed.
Rectified occasional graphical glitch with NPC's hands bend
Animations now display correctly when trading
Stomper animation now displays correctly when same target is hit by another player
Sound bugs fixed
Volume of pickup's engine has been increased
Quest bugs removed
All side quests in Laboratory can now be successfully completed
Potential walkthrough blocker removed when quest "Knockin' on Heavens Door" is completed before talking to Dominik during "On the air" quest