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