NMA mailed Leonard Boyarsky
to get some clarification on their post-apocalyptic game demos. They
asked how many PA games were in development or something, and here's the reply:
There were two different demos - the one you've
seen was using our own engine. We did another one with the HL2 engine
(using the same avatar and robot but with a Vampire 1st/third person
camera) where we took the Gargoyle's AI from Vamp and gave it to the
robot so you could fight him.
It obviously wasn't enough for a publisher. As always, there's probably more to the story than we know.