Violence in Inception is tricky to tally. At times we see real men get hurt or killed. But much of the violence is perpetuated in dream worlds, where the people we see are not real, but manifestations of the subject's subconscious. As a result, the "real" body count is surprisingly low (at least for a film that wields this much intensity), while metaphysical fatalities run off the chart.
Merging both categories, people are punched, kicked, choked, shot (scores of times), stabbed, hit by cars (several times), blown up, attacked by rampaging mobs, almost buried by avalanches and nearly drowned. Somebody gets shot in the footjust to illustrate that, while dying in a dream state is difficult, pain is all too easy to come by.
The visceral feel of the violence is about what you'd expect for a PG-13 movie and, frankly, maybe a step back from a prime-time actioner on television. The mayhem is practically bloodless (an exception: after a shot to the chest, we see red seep through a man's shirt as he coughs up flecks of blood), and it's perpetrated with a certain, almost chilly, remove.
When someone wants to exit a dream, they simply "kill" themselves or have someone do it for them. Cobb, for instance, shoots one of his compadres in the head to wake him up. (We see a bloodless hole in his forehead briefly.)
Because the sensation of falling can jar someone awake, folks routinely engineer the end of their dreams by plummeting off bridges, jumping out of tall buildings or cutting loose elevator cables. One character throws another off a cliff.
A scene is shown several times where a man and woman are lying on a train track with the intention of committing suicide.
The only blood shown in this film is when a man is shot in the chest about halfway through the movie