According to this post on GASource, Headfirst's first person RPG Call of Cthulhu: Dark Corners of the Earth, will be based on the NDI Netimmerse engine. If that doesn't ring any bells, it's the same engine used to power such games as Prince of Persia 3D, Panzer General 3D Assault, Simon the Sorcerer 3D (also by Headfirst) and um...FLW Tournament Bass Fishing. They've also posted a quote from the developer with more on the game's physics system.