Terrorist Killer guarantees collateral damage
Terrorist Killer, by Jordan Magnuson, is a game that makes a point without forgetting that it has to be a game. Tasked with killing a set number of terrorists and given foreknowledge of what they'll look like, your job is to pull the trigger when the crosshairs pass over your target.
The sights start at the top left and do a lawnmower scan of all the people gathered. It goes quite quickly, and never precisely targets all of the terrorists. When it passes near your target, you hit space to fire, and the bullets spread out and kill two or three people, including the terrorist. You're never punished for killing civilians, but if you miss a terrorist (or make too much noise and alert them), they'll set off their explosives and you fail your mission.
As the author says, it's "not subtle" - this is obviously a game where you kill civilians by accident because it's more important to your mission to stop suicide bombers from detonating. But it's also a tense, fast shooter where you're always trying to remember whether they were wearing blue burkas or blue headscarves.
Download it here.