The video goes over some pretty obscure facts, such as how the German release of Half-Life replaced HECU marines with Robo Grunts, which are more commonly known from being a selectable player skin in multiplayer deathmatch, or how the scientific equation for the exponential decay, or ‘half-life’, of an atom also happens to contain the lambda symbol as part of the formula.

See Also: Community Spotlight: Half-Life Fact Files

It’s definitely worth a watch for anyone interested in learning about the oddities of Dr. Freeman’s adventures. There is also a list of sources in the video description if you want to find out more about the facts that are mentioned.