The key to making progress without losing men is - as in previous BIA games - getting your head around the concept of suppressive fire. Each German or small group of Germans has a circular indicator above their head to show how much of a threat they pose. Send some hot lead their way and their threat level decreases. Send an awful lot and they either focus solely on the source or lose their heads completely and start cowering behind the nearest bit of cover.
This leads to the game's fundamental game mechanic. You issue move orders to one unit then your or the other team provide covering fire so that they can make it safely into position. They can then provide covering fire so that the rest of you can advance or, if you're feeling sneaky, you can get into an outflanking position and hit Hitler's henchmen where it hurts.
This worked in the two preceding Brothers in Arms and it still works in Hell's Highway, but the third game adds a new wrinkle: destructible cover. On the one hand, you now have to take into account how tough the cover is that you're sending your team into. Wooden fences or corrugated iron can be ripped apart by machine gun fire, and even loose stone walls can be blown away by shell fire. Put your men behind something insubstantial and - if you don't move them on soon - they will perish.
On the other hand, you can also call on your bazooka team to destroy weaker cover or take out machine gun emplacements behind sandbags. This doesn't seem like a huge change, but it radically affects how you play the game. It's not enough sometimes to hope that you can distract that German MG nest with your men before scampering around to shoot the gunners; you have to get your bazooka team close enough that they can put it out of commission without losing anyone in the process.
This emphasis on cover, suppressive fire and small-scale squad tactics gives Hell's Highway a very different feel from other WWII FPS games. You need to take a measured, cautious approach to each situation, probing the enemies defences, scanning the tactical map for routes and vulnerable positions then taking rapid and decisive action where necessary. Your enemies will work in teams and are perfectly capable of reacting to your ploys, so you need to think things through and improvise when the need arises.
The game uses a variation on the Call of Duty 2 health system where various onscreen indicators (here a sort of blurry red filter) indicate that you're taking damage, but once you're in safe cover you recharge. However, the amount of damage you can take before dying is minimal, so exuberant Rambo-style raids on enemy positions are nearly always fatal. The result is that Hell's Highway feels gritty and true to life in a way that recent Call of Duty and Medal of Honor games haven't. During the first few missions at least, it can be a fantastically tense and exciting experience.