I’d hope so! While the game punishes mistakes with individual Battle Brothers quite heavily, losing even most of your men does not mean you’ll have to lose the campaign. You’ll often be able to recover from losses and defeat, especially in the beginning of the game. Since you’ll have up to a dozen Battle Brothers in battle, and more than that in reserve, losing some of them won’t be as impactful as in e.g. the new X-Com game where you have just 6 men and where losing just one of them can really cripple you and send you into a downwards spiral to lose the campaign later on.
We generally also try to avoid game mechanics that boil down to pure luck and which can be beat simply be reloading. Everything should be beatable with the right strategy from the start. For example, we don’t have critical hits that do massive unavoidable extra damage on completely unpredictable random occasions. Instead, in Battle Brothers, there is a 25% base chance to hit the head instead of the body for 50% extra damage. Essentially, we flattened the curve to make this less of a random game; you’ll do critical hits way more often, but you also do less extra damage than in other systems when you do. Enough to still be relevant, but in a way that is more predictable. Importantly, you can also actively counter critical hits by equipping your Battle Brothers with headgear.
If you accept that you can’t win every battle all the time and that sometimes fleeing from battle is the right option, I think the game should be completable in ironman mode. That certainly is our goal.