Castle Totenkopf SDL is a mod for registered Wolfenstein, made by Wolf Skevos-Jones. It was released on April 11, 2010.
Essentially a reboot of Skevos-Jones' first mod Castle Totenkopf, the mod showcased many new features using the SDL engine. The sounds and music were of a much higher quality than standard Wolfenstein mods, and were found externally in the mod's folder. As such, the download was larger than 20MB, more than ten times the size of a standard Wolfenstein mod.
Other impressive features include scoped weapons, improved AI and numerous new animated objects, in addition to multiple floor and ceiling textures, a huge amount of newly added enemies and a large number of wholly new graphics.
Some maps were based on those from the original Castle Totenkopf, and some were newly made for the project.
The mod conjures up an atmosphere which in 2010 had been pretty much unparalleled in Wolfenstein modding. Up through the 2010's several mods would surface which took an approach in the layout of Castle Totenkopf SDL, most notably those of Team Raycast.