Never get into a helicopter in a cutscene: it's just not gonna work out. That's good advice for lots of shooters, particularly in the Far Cry series, and the latest example is Far Cry 5's first DLC add-on, Hours of Darkness. It takes place during the Vietnam War, where you play as a US soldier stranded behind enemy lines after the traditional chopper crash. You can watch a couple minutes of gameplay footage above.
Much as I enjoyed the Montana of Far Cry 5, it's nice to have a change of scenery, and the jungles of Vietnam are definitely a change from the woods and creeks of Northwestern US. In Hours of Darkness, you begin on the western edge of the map and make your way toward the eastern border for a rendezvous and rescue. There's still quite a bit to explore off the beaten path, however. There are outposts where POWs are being held, both American soldiers and South Vietnamese friendlies. Freeing them can give you more info about the area and add new icons to your map. You can even add a few to your roster to act as guns for hire, as in Far Cry 5's main campaign.
There are also several missions to destroy anti-aircraft guns using explosives, which is ultra important since those guns prevent you from using an extremely helpful ability: calling in airstrikes. If there are no AA guns in the vicinity, you can peer through your binoculars and quickly tag locations for strikes, and a moment later US warplanes will scream overhead and light them up for you. The planes, too, can give you additional information about the area around you and add other objectives to your map.
With the exception of jets noisily napalming the shit out of your enemies, Hours of Darkness encourages you to take a stealthy approach to your escape. Rather than the perk unlock system of Far Cry 5, you've already got four perks at the start of the DLC, but you need to make stealth kills to activate them. Make four stealth kills in a row, and you'll have all four perks active. If you're detected by enemies you'll instantly lose those perks until you've made four more stealth kills to regain them all. (In the video at the top, you can see the perks coming online as I make those stealth kills, then they go dark when I'm spotted.)
The perks don't turn you into Superman or anything, but they do make sneaking around a bit easier. The first perk lets you move faster while crouching and automatically tags nearby enemies, the second reduces fall damage and makes you move more silently, the third will auto-tag an enemy who is about to spot you, and the fourth lets you tag enemies through walls. I definitely miss those perks when I don't have them, such as when I didn't realize a look-out tower was occupied:
With only a single health bar, it pays to be stealthy, or at least make the attempt, because death can come quite quickly in firefights with more than a few enemies at once. Snipers in the DLC feel especially deadly, and are so ridiculously accurate it doesn't feel quite fair. On the plus side, crafting a medkit simply requires finding and harvesting three plants, at which point a kit is added to your inventory. In other words, sometimes the best strategy in a dire situation is to just run away and pick flowers for a while.
Here's a sentence I never thought I'd write: the Vietnam War doesn't feel quite as dangerous as Montana. After a few hours of play in the DLC, I've only been attacked twice by wild animals. Maybe part of it is due to keeping a low profile, but it's possible to run through the map for extended periods without attracting either enemies or fangs. In Hours of Darkness it feels more like you can go looking for trouble rather than in Far Cry 5 proper, where trouble constantly falls in your lap (and explodes).
I haven't completed the DLC yet, but if you're the type who has always approached Far Cry's outposts and strongholds as stealthily as possible, you may enjoy the focus on moving quietly and carrying a bamboo stick here. I'm more of a lover of loud, ridiculous combat and rampaging animals when it comes to my Far Cry, and while there are plenty of ziplines and explosives and noisy airstrikes, Hours of Darkness doesn't quite have the zany chaos I usually look for.