Switch It Up doubles the damage of Boot Knife combos. It is a Tier 5 Melee skill that makes the knife you always carry a real backup when your melee weapon breaks.
It is worth it late, once your other melee skills are done. It means you are never helpless without a bat.
Talk Shit, Get Hit for longer combos, and the This is a Knife trophy, which needs a knife kill on a big Freaker.
Use the knife on weakened enemies to save your bat's durability for fresh targets.
Bull Rush
Lets a sprinting melee attack stun a regular human or a Swarmer.
Busted Up
Restores some stamina with each melee kill.
Escape Artist
Lets you kill a smaller enemy right after breaking out of its grapple.
Executioner
Lets you stealth attack heavy Freakers, and kill heavy Freakers or large animals when breaking a grapple.