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