From the back of the book:
A GRINDHOUSE HORROR RPG
PHANTASM (2010) is a complete tabletop roleplaying game made in tribute to the Phantasm series and other seminal works of grindhouse and horror genres, such as Hellraiser, The Crow, and the Evil Dead series.
PHANTASM (2010) is a part of the Cinema6 rules system, but all you need to play PHANTASM (2010) is this rulebook and a few six-sided dice.
Cinema6 is what Devon named his cinematic D6-based series, and Phantasm (2010) was the first in the series. Unfortunately, he never Googled it to find it was already in use with half a dozen titles. This is why my PDF and physical copy refer to Cinema6.
When it was brought to his attention recently that Cinema6 was already in use, he selected "DicePunk" as his system name and they've updated the PDFs to reflect this (apparently, after I had downloaded same). Phantasm (2010) is soon to be reprinted and the new physical copies will refer to DicePunk.