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