Titan Panel [CritLine] records your highest normal/critical damages and heals. It lets you know when you break your previous record high with a splash message on the centre of your screen. It also displays a detailed summary when the Titan Panel [CritLine] section is moused over on the Titan Panel. This summary includes your targets name, level, type of attack, and damage.
Titan Panel [CritLine] is a port of CritLine (orignially by Sordit). If you want to use CritLine and don't want to use Titan Panel, try one of the various mods labeled 'CritLine' on this site.