Developer room...
	Easy "Major Pain" trophy...
	Various Trophies...

Go to the Hunting Ground area from the upper right side of the home camp instead of riding the chopper to a mission. Progress through the Hunting Ground until you reach a grassy ledge with a tombstone and flowers. Continue to the right from there. Search for two brown nubs that are close to the wall that blocks further progress in that direction. The nubs are actually the top of a hidden ladder. Climb down the ladder, then move to the right until you reach another wall. Roll to pass through the wall, then continue moving to the right on the map. You will pass through some chambers before reaching the hidden developer room. You can talk to each of the developers and receive secret gun pieces from several of them.

Healing by using an Infirmary is will not affect progression. The difficult part is completing gathering/rescue missions solo. Bring C4 when performing any gathering or rescue mission (that involves multiple hostages). Because you can only call in one C4 it must be used very strategically. The order in which you rescue hostages, collect coins, and destroy bombs must be done with C4 efficiency in mind. To save time and health, carry armor piercing rounds with long range. This is especially useful during "destroy 5 bombs" and "rescue [number] hostages" missions. With long range armor piercing rounds, you can rescue hostages from a distance and through walls (especially in the large middle room of the temple). You can also destroy bombs without entering the Boss area, thus skirting those fights.

Complete the following tasks to unlock PlayStation 4 trophy rewards.

Trophy	How to unlock
Baron Bashing (Silver)	Defeat Commander Byron Baron once.
Blastfighter (Bronze)	Complete a mission with all parts of the SWAT-12 shotgun equipped.
Cold Hearted (Bronze)	Complete No Negotiation without saving any hostages.
Coronation (Gold)	Clear all missions of the game.
Craftsmanship (Gold)	Craft over 100 knives and 300 gun parts.
Decorator (Gold)	Craft 20 Ornaments and 20 Banners.
Denied (Bronze)	Defeat a boss before it can escape.
Executioner (Bronze)	Defeat over 1000 enemies.
Favorite (Silver)	Clear all missions of any rank consecutively using the same gun parts.
Five-Star General (Silver)	Reach the Five-Star General rank.
Foodie (Bronze)	Activate all 14 food skills.
Grim Reaper (Bronze)	Defeat over 10000 enemies.
Hoarder (Gold)	Collect over 2000 materials.
Imperium (Platinum)	Mandragora Island is now your dominion.
Is That A Knife (Silver)	Defeat the Steel Soldier using only your knife.
Jack Of All Trades (Silver)	Unlock all Proficiencies.
Liberator (Bronze)	Rescue all 6 Kickstarter backer hostages.
Major Pain (Silver)	Clear all Major rank missions without using Rations nor First-Aid kits.
Medic (Silver)	Revive a teammate 10 times with the Adrenaline Shot.
Millionaire (Bronze)	Earn over $1,000,000.
Pistol Pro (Silver)	Clear all 10 Primary missions of the game with the Bolt 45.
Poacher (Bronze)	Hunt over 250 animals.
Speed Runner (Gold)	Beat the fastest time of all missions of the game.
The Bionic Merc (Silver)	Craft all Bionic Mods.
Untouchable (Gold)	Complete a mission in single player without getting hit.
World Hero (Gold)	Defeat the final boss.