Well, the fact that the original Titan Fortress is a "Fatal Four Way" means that it's not exactly free-for-all. My original intent with that was to make it a closed-circuit, more controlled Deathmatch map. For starters, the stipulation was that you are only limited to fights in the central "hub" of the map, and the four of you would have your own quadrant of the map to play in, and you'd have your own pickups, your own weapon, your own ammo, your own armor, your own health, powerups, etc... If you went into another player's quadrant, my intent was to penalize you in some fashion, whether it be 10 health points deducted, armor reduced by half, something along those lines, if you were out of bounds or offsides, or whatever that penalty was. So yeah, it's a more restrictive version of DM, and I may probably make the prefix "DM-4Way-TitanFortress" in its final phase. Well, I think that I would probably put like a lava or slime river to set a boundary for everyone.
Now, for the 1-on-1 version, I may probably have it a little simpler. You'd have your lava river keeping you on your half of the map, and you'd meet on the boundary line, and have it out there. It's more on the lines of what you had in the old days with 1-on-1 duels, triple threats, and fatal four ways, so for UT2004 and UT3 it's a concept, but it's been done in real life since ancient days, where you set boundaries in a firefight.