Lots of fighting against clones that includes stabbing, cutting, and shooting. No gore at all, and only one part has a slight bit of blood. Though there is blood in other parts.
Some fighting includes hitting with fists, feet, nunchucks, rifle handles, and a baseball bat.
The only moments in season one that have blood include Wendy cutting Vicky's cheek in "Nightmares", Andrew hitting Joy's face with a rifle handle in "Escape," and a neck slice (looks like the knife sliding on skin) and stab both from "The First War".
Some stabs show the knife clearly in the body, but it looks like pushing a handle against them as we see no blood or skin separation.
In "The First War," two people have their necks snapped and we hear a crunch.
A bomb is mentioned in "Nightmares" and used in "Escape"
Many episodes show Andrew or Joy using a pair of gloves to telekinetically throw/shock someone.