Columbine happened in the 1990s. I remember when they came out with the DOOM map for it. In the 90s. I never actually played it, but I kinda wanted to.

I feel like if Blood came out after Columbine, they would have had a school level. They did have a grocery store level. Blood was more like Duke Nukem 3D, way more advanced than DOOM, but still that same generation (what people now call boomer shooters).