Project: Infiltrate is a mod for registered Wolfenstein, made by Zach Higgins.
Made in 2001, and predating Projekt: Vertilgung's demo release, it was only released in March 2003 for kicks, with Zach almost apologizing for its release.
3 levels of fair size are featured, and what would eventually become Projekt: Vertilgung is definitely felt in the mapping. Graphics come mostly from Totengraeber and Operation: Panzerschiff, a typical trait of many 2000/2001 mods.