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