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