You always hit if you point to correct direction. Is not necesssry look up down.
Even if you are not looking up and down, you still need to be able to TURN while strafing in order to dodge while placing the crosshair on top of the enemy.
Doom has no crosshair by default but you don’t really need it, it’s pretty easy to aim since the gun is centered.
Duke 3D has a yellow crosshair by default. Press the key “I” if you can’t see it.