In WOFF, promotion rate seems to depend on how many kills you can get.
I was thinking of doing a simple tweak to a file to make the player's bullets do only half or quarter of the original damage while enemies stay at normal damage. Kinda like hardcore or survival difficulty in games.
This tweak and my limited head movement MOD would make scoring victories a bit more challenging, but not impossible. Thus forcing the player to use survival instincts over shooting an enemy down and reflect more realistic numbers and promotion rate.