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