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