Oh yeah, an addendum to the prior post:
HELL GAME is open source now.
The git repo is over here; it's actually ahead of the live version being hosted here in that it has a new body tree editing tool + some half-implemented data for NPCs also having body trees, plus some additional misc. changes like that. You'll probably have to build it from source yourself; I have one pre-built 'release' that would only work on linux and might not work at all.
I don't really have any immediate plans to work on it more, though I might at some point go back and try to untangle the mess of the event code so that it's actually usable for its intended purpose (e.g., moving NPCs around between locations dynamically). But nothing much planned right now.
EDIT 2021-01-28: that git hosting site went down so here's a big locally-hosted .tar.gz of the source + git repo.