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