"Beware of a Pissed Off Marine"

You're a soldier arriving by boat in the country of Vietnam.
You're in a squad of the Marine Corps and are being brought by heli to an airfield base where you will stay during your time in the war.
Your task will be search and destroy missions, searching for the enemy and destroying their positions by insertion by huey's.
Further you will have to fight your way trough a city or two wich will possibly take multiple days.

The year is 1968, the North Vietnamese Army for the first time is attacking big Southern Vietnamese cities and US and SVA bases and even treathening the South Vietnamese Capital.