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