Operation: TREBUCHET is a mod for military simulation ArmA III that transforms it from a realistic armed forces shooter into a massive Halo game.
While it’s been in development for a few years now, there’s a new trailer for the project that looks fantastic:
Named for the UNSC’s war against insurrectionists just before the Covenant invasion, Trebuchet is a total modification for ArmA III that changes almost everything about the original game, adding stuff like custom Halo UI to vehicles and weapons, new buildings and even Halo-appropriate environmental props.
The idea isn’t to just turn everyone into a Spartan and let you go at it; instead the mod wants you to experience space war from a grunt’s perspective, and “bring the popular Halo Universe into a more realistic setting by introducing it into Arma 3.”
Trebuchet is currently in alpha, and you can check it out at the project’s Steam page.