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