It's also a game people play in person as well. It's the same as the Halo version except you tag each other instead of shooting. It's really fun to play in big open areas with large teams.

Yeah.

As I remember it (and this was decades ago): Two teams, opposite ends of a large field. Each end gets a "flag". (We used t-shirts.) In our case, we split the field in half — our field happened to have a natural feature (a change in elevation, so like two separately flat areas separated by an incline) that worked well for this. If you were tackled¹ in the enemy's side, you were "captured", and "jailed". An uncaptured player could spring the jail by tagging those within it. Returning to your flag with the opposing team's flag was a win.

We played at night, so stealth was a large part of the game, but it was also fair to illuminate the area around the flag. (Which made approaching a guarded flag … tricky.)

I'm sure there's probably a million variations on the specifics.

¹…flag football flags would probably work nicely for this.