Operation: Vietnam DS review at IGN.

"Four men get lost in the jungle. You've got to get them out. With the help of some guns and grenades, a few called-in helicopter airstrikes, and the occasional swear word Operation: Vietnam asks you to take command of a quartet of stranded soldiers in the middle of the Vietnam War and make sure they get back home in one piece. But, even assisted, it might still be difficult to do – because in addition to outrunning enemy forces, you'll also have to fight back against this game's murky visuals and troublesome control style."

Full Source: IGN