In a deserted city like in the Resident Evil with Zombies around The three characters have the ordinary weapons Hand Guns grenades multi visual tool a Sniper Rifle and a assault rifle and a Bowie Knifes. Alice has two Handguns,Shot Gun and Survival Knife. Nemesis has a M60 assault weapon with a RPG on the M60.
Agent 47 has a hit rate of 100%, it is not likley that he misses. One shot and he kills Alice. Both Agent 47 and Snake can dodge bullets (not like matrix, but both have shown the skills to avoid at least 1 shot).
Snake has taken down enemies far beyond Nemesis (though he might have better equipment at that time), even if it's too much he got both Sam and Agent 47 to help him.
Nemesis might kill one of them with his rocket (most likley Sam, Snake has dodged rockets before) though.
That's what I think.