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