So this thread will explain how Lithium's abuses the source engine's lag compensation.

If you want to understand how lag compensation works then watch this video.

Note: Backtracking only works on lag compensated weapons.

The options.

Normal (Aimbot only option)
So the way this option functions is that it will only aim at back track positions if there is something invalidating the player. And what do I mean
about "something invalidating the player" is related to the player not being visible, using invalid pitch angles or breaking lag compensation. However in most cases it won't use back tracking at all if they're breaking lag compensation because well... Back tracking abuses lag compensation and if they're breaking it then there is really no point in using something that is broken for them at least. Lag compensation can "break" if players are using fakelag and moving at high speeds.

How normal back track works on cheaters.
During the aimbot's "cycle" it will detect if the person is a known cheater or if the player's pitch angle is out of range. If that happens it will check every lag record to see if there was a tick where their pitch wasn't invalid. If it does find one it will move back to that exact tick and aim where ever that person was at.

How normal back track works on every player.
So in event somebody kid runs behind a wall. It will check every lag record to see if they were visible during that tick. Obviously, if they were then it will move back to that exact tick and aim where that person was at.

Last tick  (Aimbot only option)
This feature pretty much uses the same code above. However it always aims at the oldest tick.

What are the other options?!
I shouldn't have to explain what the visualize options do but... You know, just in case somebody is New!

Aiming mode  (Doesn't affect aimbot)
This one works by simply automatically moving from tick A to B or B to A based on your cursor position of the player. This means you can shoot about 5 feet(not a real value) behind a player but magically hit them still. Obviously, by the name of the option is the directed towards "legit" cheating game play.

Visualize
Both of the visualize option for non local player and local player will do:
Display a skeleton of the player at the oldest tick. You have to be in third person in order to see your own skeleton. Scary stuff right?

Wait!  (Aimbot only option)
What this option will do is that the aimbot will check to see if there is any valid lag records on the player. If there is no valid lag records on the player then it will simply
ignore the player. It can be useful and not really so useful hence why there is an option for it.