About Fallen Lords: Condemnation

The biblical content is very superficial in this.

Many faiths and texts have angels, demons, and an afterlife. I see no Christian or Holy Bible specific connection regarding this game. It cannot even be called Judeo-Christian mythology as far as I can tell.

Very few others have the War in Heaven thing going. Personally I recall no others with it.

Though speaking of which, War in Heaven could be introduced as a tag referring to the bible thing but used more as source of inspiration than literal reference to it, it's fairly popular one as far as big conflicts go.

Then please read more. Keep in mind that Milton's writings are not canon nor consider Holy works by anybody except maybe in Hollywood. Most entertainment uses of the War in Heaven can be traced to Milton, not any religion's holy texts. Here is something key to remember about Milton, "Satan" and "Lucifer" are never explicitly identified as the same individual in any ancient text; Milton was the first. It is true that a "War in Heaven" has been emphasized in Christian writings and tradition more so than other faiths. Lesser known writings associated with Judaism (not the Torah, directly) also talk about it. Islam mentions it. Mormonism devotes more text and teachings to the it than most others (Less though than Christianity, I think, I could be wrong). The Essenes collected many texts concerning it, and the Essenes are admittedly an influence in Christianity. But, the vast majority of their materials on the subject are not canon. More than one conflict between gods resemble a war in heaven in Greek myth; the Olympians vs. Titans most of all, but also Protogenoi vs. Titans. War in Heaven is ancillary to all of these faiths and I doubt there is any surviving faith that treats a war in heaven as fundamental.

Bottom line, "war in heaven" might but does not automatically equal Christianity.

Is war in heaven the only possible content in this matter?

I don't recall the game much anymore and information lookup on it was challenging, so I can't say more certainly than that.