Came Back Wrong: Two examples. In one Strontium Dogs strip, he is back in constantpain until the Gronk gives him a Mercy Kill. During The Life And Death Of Johnny Alpha, he comes back with a parasitic spirit inhabiting him. Even when he gets rid of it, he's more ruthless than he was during his first life.
Combat Pragmatist: Johnny's time as a guerilla soldier during the Mutant Uprising seem to have left him with a distinct aversion to anything remotely resembling a "fair fight". Knuckledusters, explosives, booby-traps and Time Travel weapons are regular parts of his arsenal.
Our Vampires Are Different: Immune to diseases and toxins and doesn't age. She has long fangs and uses them to drink blood from people and animals, which she needs to survive. Red's condition is a strontium 90-induced mutation and in no way supernatural, and is never treated like anything else.