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