SO much fun. God, I love this game.
The Inquisition doesn't hardly give you shit accept for jobs that'll, more than likely, get you killed. In fact, some of the last people you should trust are your handlers (your not likely to know your real master, your Inquistor, until you've survived a few suicide missions and been deemed "useful"). Acolites are half secret police and half cannon fadder.
Tier five or six Acolites, like you guys, have passed that point and you know of and may have even met the dude who's constantly getting you into trouble. While he hasn't given you anything directly, he makes it possible for you to get things for yourself, like chainsaw swords and bolters, both of which are very rare and valuable items, normally reserved for the Emperor's best. Humanity forgot how to make them ten thousand years ago, what exists today has endured since then.
Bolters come in three shapes: psitol, rifle, and heavy. All of them fire, surprise, bolts! Bolts are .75 calibur solid rounds. Each one has a casing with enough packed explosive(gun powder or like material, depending on when/where it was made) to get it out of the barrel of the rifle and ignite the self-propellant. Once free of the barrell the bolt's internalized fuel lights and the bolter accelerates away from the gun, gaining speed as it does so. Designed to adjust to soft (flesh) or hard (armor) targets, the bolt penitrates to effective depth and then detonates.
As for rooting out heresy, first you have to identify it.
Depending on your Inquistor, you'll find different things to be different levels of heretical, and that these levels may or may not be acceptable. The Adeptus Mechanicus are, in many ways, heretics. But they are the prayer keepers, the only ones who know how to keep the machine spirits appeased and functioning. So, it can be tough. Luckily, you have a clear guide to heresy: those outside the Emperor's light.
This includes:
those who deny the Emperor,
those who worship others aside from the Emperor,
those who worship others inaddition to the Emperor,
those who do not worship the Emperor,
humans who complain about being human,
humans who don't want to be human,
humans who mutate into other things,
humans who mutate into slightly different things,
humans who talk to aliens,
alien in general,
anything that belongs to aliens,
anything that belongs to daemons,
people who worship daemons,
people who work for daemons,
people who talk to daemons,
people who look at pictures of daemons,
people who know anything about daemons,
people who think about daemons,
humans who use sorcery,
humans who think about sorcery,
humans who learn new things,
humans who teach new things,
and planets who don't pay the tith.
There's more, but that's the primer. Within the Inquisition there are three massive orders: Hereticus, Malleus, and Xenos each specialized in the destruction and removal of one of the three major problems of the Imperium: heretics, daemons, and aliens. Honestly, all of them are heretics but the lines have to be drawn someplace.
As an acolite, you are a secret agent. You don't say your part of the Inquistion, you just move about and watch. When you find heresy, consider: is this it? Heresy is like a weed with deep roots and it spreads quickly. Kill one heretic and you will simply have to kill another soon. Follow one heretic to it's nest and you may kill many heretics, then you can move to a new place for more.
Or the roots may go too deep. You can not know who has fallen. So the planet will be burned. Each citizen put to their own pyre. Burn them all and the Emperor shall know his own. Your job is to find out when this must be done. More often, of course, the heresy is not so deep and limited to a select few. Once you know the truth: burn the witch.
Unless, of course, you can't. The rich and powerful are often as weak as the gutter slime. When a planetary governor falls to dark worship, what are you to do? Find the proof, reveal all, and then to the stake he goes.
And remember, the battle is never won and you will never be remember for anything you do. You name and your life will be meaningless to the entire Imperium and a hundred thousand billion human lives will take no notice of your existance. And you are all the protects the Imperium from destruction by alien and demon. You will do your job. You will die or go mad (and then die). And you will be forgotten.