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