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