There are many special achievements in "Stalker 2: Heart of Chernobyl", and Walls Have Ears is one of them. The requirement for the achievement is to kill 50 enemies through obstacles. In the mutated zone, no one is truly safe. The difficulty is not too high. Human enemies will often hide behind cover and wait for them to hide before killing them.
How to achieve the achievement "The Walls Have Ears" in STALKER 2: Heart of Chernobyl
Partition walls have ears
Kill 50 enemies through obstacles. In the mutated zone, no one is truly safe.
Target and kill enemies when they are hiding behind cover or obstacles. Mutated enemies will not hide behind cover, as human enemies often do, wait until they enter cover and then kill them.