UnMetal Achievements

There are a total of 40 achievements/trophies in the game (PS4 version has 41 as it includes the standard Platinum Trophy for obtaining all other trophies). These match up with each consoles own Achievement/Trophy system where applicable.

The PC, Switch and Vita versions require the collection of an in-game medal to unlock an achievement's mission, though any progress towards the mission before the medal is obtained is still counted. The achievement is only granted if the corresponding medal was also picked up, regardless of whether the achievement criteria was met. The PS4 and Xbox One versions do not include these medal pick-ups and achievement missions are unlocked and granted automatically.

It is worth noting that once an achievement has been unlocked, it remains unlocked indefinitely. This means you can unlock an achievement and then immediately load your last checkpoint and the achievement will still be unlocked. This however, does not count for achievement progress, which does revert back when loading a prior checkpoint.

THE GREAT ESCAPE - Complete Chapter 1
SOMETHING STINKS REALLY BAD - Complete Chapter 2
IN THE LION'S DEN - Complete Chapter 3
WELCOME TO THE JUNGLE - Complete Chapter 4
THE BARRACKS - Complete Chapter 5
ENGINEERING PROBLEMS - Complete Chapter 6
BOOM DOCKS - Complete Chapter 7
A THOUSAND EYES ARE WATCHING YOU - Complete Chapter 8
JERICO'S HEART - Complete Chapter 9
ESCAPE COMPLETE - Complete Chapter 10

SERGEANT - Reach Level 2
LEUTENANT - Reach Level 4
MAJOR - Reach Level 6
COLONEL - Reach Level 8
GENERAL - Reach Level 10 (you need 117xp out of a possible 133xp to reach Level 10)

CONTINENCE - Complete the game using no potties
SORT OF CHILDISH, DON'T YOU THINK? - Neutralize 5 guards using the slingshot
AS YOU WISH - Heal 20 guards
GOOD NIGHT - Put 20 guards to sleep
POTTY TIME - Obtain 5 potties (Locations: Chp1 jail cell with sleeping guard, Chp1 jail cell with prisoner, Chp3 cubicle in first toilet, Chp5 getting the guard's note signed, Chp7 first screen middle container)
LORD OF THE BULLETS - Have 90 bullets or more (Requires taking Light Munitions Expert at Level 9 and finding 10 of the 12 bullet slots)
SECRETS - Find 15 secrets in the game (Note there are 21 Secrets in the game: Chp1-1, Chp2-2, Chp3-2, Chp4-4, Chp5-2, Chp6-2, Chp7-2, Cph8-2, Chp9-3, Chp10-1)
KNOCK KNOCK - Break all toilet doors
YOU'RE A TOUGH GUY - Finish the game in hard mode
THE STEALTHY EXPERIENCE - Get the maximum experience possible in at least 5 chapters

Chapter 2

THE SMELL OF NAPALM - Craft a Molotov cocktail (Whilst this can be achieved at any time, the bottles and fuel are obtained in Chp2)
SHREDDED TUNA - Kill 5 Human-Piranha-hybrid things with the shredders
COLD AS ICE - Defeat SEWERJUNK without damaging it with the Flamethrower (you must pick up the achievement medal before defeating Sewerjunk; you are allowed to break his tentacles with the Flamethrower as this does no damage to his health bar)

Chapter 3

RAGE AGAINST THE MACHINE - Destroy 5 drones by punching them (could also be done in Chp10)
COLLATERAL DAMAGE - Die while tempering with items from your inventory (combine Sodium and Water)
THERE IN 60 SECONDS - Reach the ground level in less than 1 minute when running to save the doctor

Chapter 5

FINDERS DESTROYERS - Destroy 5 trucks in the north parking lot at the barracks before Machine Mike does with his tank
SPLASH DAMAGE - Let SPLASH MIKE destroy all crates and trucks at the barracks (note, this wording is incorrect, the achievement simply requires all crates and trucks to be destroyed, you can help destroy them)

Chapter 6

JUST SOME BOXES - Destroy 5 crates with a single grenade (done with the 5 crates in the top corner of the first room)
UNAGI BLAST - Defeat HUGEEL firing just 6 torpedoes

Chapter 9

MECHA-RACHNOPHOBIA - Destroy 9 mechanic spiders
LOOK AT THIS PHOTOGRAPH - Obtain Robert's photographs
DANCE OF THE BLADE AND GUN - Defeat TAKUMA TAKAGASHI without letting him heal himself (you can pick up the achievement medal after the boss fight is over and the completion will register)
DO NOT DISTURB - Complete the catacombs without destroying any cell gates