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