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