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