Alright, so let's workshop this.
What are the core elements of Divine Fire?
1) Isolated facility that appears deserted
2) Foreign territory to the players (likely a foreign country as well)
3) An inability to leave said location
4) A reactor or other generator that is tapping into another dimension
5) Subtle mutagenic effects covering the area
Divine Fire itself uses a German military base while the version Glancy did used a Libyan military base.
Grunfeld, the ghoul behind the locked door, is another constant.
Any major elements I missed?
Usually an insane character to give half believable exposition before meeting Grunfeld.
Many survival horror tropes, such the aftermath of suicides, massacres and a constant low level of "something" lurking in the shadows waiting to do them in next.
One of the things I liked most was the discovery of the medical area, where the players find out that they were sent to the facility to become the next round of test subjects. Something about the disgusting fate that they narrowly avoided giving them a reason to not despair for a moment, then shocking them back into the reality of the situation with an attack is always good.
Sure you avoided THAT fate. Now do something about this one. Also I am not afraid of giving them weapons since the baddies are tough in this scenario. Mutant horse/elk thing and the col. are the boss fights, everything else can be exposition or you can throw in some mutant types to up the ante.