I noticed a lack of comprehensive 100% achievements guides for the original version of Metro 2033 while I was preparing for my own run, none in english anyway. I decided to look elsewhere and bring the guide here instead, finding one such guide on trueachievements.com which included both the achievements for the base game and the Ranger DLC/update.

All credit goes to Jayour, dropK1CK ninJA, and LV 1 Blue Slime for creating the guide.