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