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