Commence high-budget inter-developer slapfight! Duty Calls is Epic Games' riposte to the slew of military shooters on shop shelves: specifically Activision's Call of Duty series. The eagle-eyed among you might've noticed that from the name.
tells the serious and profound story of Some Soldier Guy, who's sent on A Serious Mission to kill A Bad Dude With An Eyepatch And A Dreadful Accent. Highlights include unlockable ranks (all the way to 'Sergeant of the Master Sergeants Most Extreme Person of Extreme Sergeants to the Max!'), a wide range of pickups (two, ranging from a stick to 500 sheets of wide-ruled paper), and an incongruous slow-motion section. All bullet sounds are replaced by the word 'boring', and each enemy announces his presence by way of describing exactly what he's doing at that moment. All in the name of building narrative, of course.
Conveniently, it also doubles as a promotional item for Bulletstorm. Duty Calls weighs 700ish MB, and qualifies as a big-ass download. Therefore, in the interests of saving your bandwidth (hello, Canadians!), I've posted screenshots of my playthrough below. It's all free, even if the install takes far too long.