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