Cool! This project started out as a way to learn Gr library routines in HolyC, and kind of Frankensteined its way into a game engine. In the coming weeks I'll be doing lots of refactoring to bring the code in line with proper TOS guidelines naming conventions.
(Author here: I cross-posted this comment from a reddit thread, hope it isn't against the rules..)
I've been dabbling in learning TempleOS programming for a bit, did a host-guest driver giving VMware Tools-like functionality, minimal web browser, Mega Man game engine & DOS demoscene style intro, Github stuff is here if anyone's interested: