Here is the full list of all 49 Metro: Last Light Redux achievements. It takes around 30-35 hours to unlock all of the achievements on Windows.
Complete all 43 of Artyom's hidden Diary pages.
Save D6.
Complete the game in Spartan Mode.
Kill Pavel.
Complete the BRIDGE level without a kill.
Remove your mask when Lesnitsky demands it.
Find and return the crying child's Teddy Bear.
Drink at every occasion.
Complete the REVOLUTION level without killing and raising an alarm.
Kill the Watchmen attacking the Railcar without taking any damage.
Kill all armed enemies on the REVOLUTION level, including all reinforcements.
Watch the entire Theater Show.
Complete the ECHOES level undetected by the Watchmen.
Complete the FACILITY level without killing or raising alarm.
Complete the SEPARATION level without killing or raising alarm.
Escape the chasing Nazis on the REICH level without being caught once.
Finish the ASHES level without taking a hit.
Spend 1 hour on the DEVELOPER level.
Complete the TOWER level.
Make 10 Spiders flip belly-up.
Complete the SPIDER LAIR level.
Complete the PAVEL level.
Kill 10 enemies in a row with Throwing Knives.
Complete the SNIPER TEAM level.
Complete the KHAN level.
Complete the ANNA level.
Complete the KSHATRIYA level.
Complete the HEAVY SQUAD level.
Free the Prisoners.
Destroy D6.
Complete the game in Survival Mode.
Make Moskvin tell the truth with help from the Dark One.
Save the Bear from the Watchmen after the fight.
See all Visions in the Dead City.
Disarm 10 Traps.
Find out about the Reds' plans.
Open 10 locked safe boxes.
Kill the Rhino.
Kill 100 Mutants.
Rescue the Women and Children on the BANDITS level without raising alarm.
Turn off 40 Lights without breaking them.
Kill 100 Human Enemies.
Spend 30 minutes' worth of Filters.
Stealthily kill 15 Enemies.
Use 10 Lever Switches.
Escape from the Red Line.
Burn 50 Cobwebs.
Complete training sequence.
Choose three primary weapons that use different ammo.