I mean, yeah. If someone doesn't like the sight of blood or death, should they work as a doctor in an emergency room? Probably not. Should they work for a software developer that has depended on that kind of thing for many years? Hm.
Why didn't he just say that it wasn't for him and resign?
I am also wondering if it's company policy for the person to view such material or did the person do that on their own so that they can think up fatalities and brutalities. When you think about it, if such material gross you out or causing you issue, it probably would be best not to do it. If the person continue to do it they have to take responsibility for their decisions. If you have watched any of the mortal kombat games, the fatalities and brutalities are pretty graphic. A lot of people are not cut out for that kind of graphic work. That's like someone trying to be a war reporter but get PSTD from filming such scenes.