Spartan vs. Ninja immediately disproved the "skill always trumps power" trend that began with Gladiator vs. Apache and Viking vs. Samurai. The second instance of "power" trumping "skill" is Vlad the Impaler vs. Sun Tzu.
Atilla the Hun vs. Alexander The Great was the first simulation battle to have extra soldiers (who end up as mere fodder) alongside the main fighters, but Jesse James vs. Al Capone was the first to have a squad battle with leaders.
Jesse James vs. Al Capone was the first squad battle that ended with more than one of the winning team left standing as opposed to just one man remaining.
The KGB vs. CIA was the first battle that featured females in combat (their first actual appearance in a combat scenario was Mafia vs. Yakuza as a bystander).
The Ming Warrior vs. Musketeer is the first team battle that takes place without any buildings in sight.
The Navy SEAL vs. Israeli Commando is the first battle that had a weapon perform a polykill in the simulation.
While that battle had a polykill as the last kill, a polykill was the first kill in Saddam Hussein vs. Pol Pot.