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