This was an amazing version of FORTH for developing games on the Commodore 64. In 1985, I bought White Lightning (which came with Basic Lightning, an extension of the ROM BASIC). This FORTH could multi-task on a Commodore 64 by specifying a FORTH word to be executed when an interrupt occurred. It even had up to 255 variable-size software sprites (BOBs or blit objects).
Disk image for C64 emulators is available (a website had it named dm029.zip). Documentation is available at bombjack.org, along with other ancient Commodore artifacts.
Oasis Software had a review in Compute! Magazine #066 Nov 1985. Here is a PDF of the single page.
The above advert was in Compute's! Gazette Jun 1985. Here is a PDF of the single page.
Send me an email, as I'm curious how other people used it, and if White Lightning was ever used in commercial C64 games (update: answer is yes).