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