If you've never played it you haven't missed much
The most aggravating aspect of the game are certainly the super-natural abilities granted to the AI enemies. Peasants wielding the high recoil AK-47s at improbable distances become deadly accurate marksmen. When both you and the enemy are obscured by vegetation they can always somehow hit you as if your character was wearing a homing beacon. Lay prone and you still get shot. You'll see anonymous tracers of rounds fired by the not yet rendered enemies over the horizon tearing you to shreds with little to do about it. They are somehow allowed to slip through the aforementioned "green wall" as well as shoot through it. At times bullets even penetrate walls. You'll regularly encounter invincible machine gun nests which are allowed to spray rounds with impunity as their personnel is always bulletproof and you'll have to partake in a suicide mission to mark them with smoke for the artillery. When time comes for your character to get behind a fixed machine gun though you enjoy no such immunity and become a stationery target. I don't recall another shooter where it was this easy to get killed. I observed instances where my character got shot just once and the health meter went down by 90% (this all happens at normal difficulty). At the same time you can empty your clip into the enemy and he keeps running. In terms of player aggravation this game has no equals. The developers obviously didn't grasp the fine balance between challenge and playability or fun. The player has to be able to believe that success is attainable as you learn and get better in a particular scenario. There's nothing to learn in this senseless mayhem where all things are so overwhelmingly slanted in favor of the enemy that it should have been named "Suicide Vietnam".
"Dear Mr and Mrs Roland Shepherd
It is my sad duty to inform you that your son perished on the virtual battlefield of Vietnam. He died of boredom and frustration while reviving himself for the 507th time in yet another poorly thought out and scripted scenario of this half baked and forgettable shooter. Let the rest of us hope that through his sacrifice we'll be saved from such dreadful affairs in the future."