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