> a game that would never be released
Halo was released to Xbox in 2001 and by 2003 both a MacOS and Windows port were released. "Delayed" maybe, but definitely not "never released".
I played quite a bit of Halo on PC in high school with my friends, sneaking into a nearby university computer lab and usurping it as a LAN party room. For some reason those Windows machines all had Halo pre-installed on them.