Some thoughts on "Terrorist" horror videogames games:
I think it would be a lot more profoundly disturbing and effective as a horror title if instead of being the Terrorist, stalked by superagent fisher/snake/etc, you were a random pedestrian thrown into a terrorist or active shooter scenario. Picture, if you will, a game with no HUD or music, where you're riding a subway, say, when it comes to a stop and a single or pair of shooters walks in through the door with a shotgun and rifle and opens fire. Options for escape are running and hiding or playing dead, though compounding the issue is the disorientation, lack of direction and stumbling and tripping on other panicked NPCs and scenery collision mesh. Additionally, you could also play as medical response, saving lives by assessing the injured from the dead, while the situation is still hot and dangerous.
In a less urban or first world context, you could be a political 'threat' running through the bush trying to throw death squads, police and search helicopters tasked with bringing you down, by the despotic government you had the audacity to speak against. Perhaps beyond merely surviving, your mission would be to bring video documentation of human rights violations to a whisleblower. Something between Sir You are Being Hunted and SPEC OPS: The Line, tonally.
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On the complete flipside, it might be interesting to play a Terror cell leader in a game whose turn/metamission mechanics resemble XCOM and whose missions play out like an automated Rainbow Six / DoorKickers / Frozen Synapse plan-->execute. Successful acts that garner intense media saturation increase your shady funding and resources of mercenaries, suicide troops, weapons, explosives, and eventually WMDs.
Now, all of those, perticularly the third are hot button issues that would likely cause a lot of fuss and discussion, or outright condemnation of a game in which you orchestrate increasingly horrible massacres. If someone made them, they'd really have to double down on making such a unflinchingly awful project with headline horrible plot points. Yet, I feel there's potential for profoundly affecting games there, if handled correctly. It would not be difficult to come off, crassly, as mere shock and exploitation.