Why does the doomguy shooting at the wall kill enemies?
In this very long video, the player shoots rockets at a wall, and it does damage to monsters.
What's going on here? Which bug/feature is this?
Doom 1 and 2 are not truly 3D. All the game physics and hit detection assumes everything is at the same height, even if it looks like it's not. So even though there is a large total distance between the enemies, most of that distance is vertical. The horizontal distance is very small, so the enemies are still within the blast radius.