Chemical Warfare is a mod for registered Wolfenstein, made by Liz Ryerson. MCS and Chris Chokan helped out with the coding.
It was released on April 7, 2002. Essentially a retelling of the original game's Episode 4, the player is taken through 42 levels of high quality and with much variation. 37 levels are regular levels, with 5 of them being secret.
Coding features include the missile launcher, seamless level flow, end level objects, and on some levels (e.g. level 29) tweaks to pushwalls.
New music is also featured, original melodies composed by Chris Chokan as well as Liz herself, in addition to original Wolfenstein and Spear of Destiny music.
Some levels have a number of Hitler bosses on them, and in some few cases there is a shortage of ammo. Though difficult at times, the player is rewarded in plenty of treasure and easily accessible one-ups.
Wolf4SDL Port
With Liz's approval, a Wolf4SDL port of the game was released by MCS on July 27, 2019. It was developed sporadically over the course of seven years, with testing by Thomas.