Pistols

Piercer: The piercer pistol is used to do high damage in a burst to multiple enemies in a row. If you aren't using the alternate revolvers, aim for the head when using a charge shot. There isn't much to say about this one, use it against more tanky enemies (Malicious Face, Cerberus, etc.)
Marksman: One of the most powerful weapons in ULTRAKILL, I highly recommend using this weapon. The alt. fire for this gun throws a coin, which may not seem to do much, but, if shot/punched, it will do a more powerful, homing version, of the regular shot. This is best used against drones, like in 1-1, however, it is powerful in all situations. Simply toss the coin, and quickly snap your camera upward until your crosshair is on the coin.
Sharpshooter: I don't realy have much knowledge about this pistol, I would use it in enclosed spaces, or to deal quick damage to an enemy.