gonna start updating this a bit, as it seems to have stagnated.
so: recent feature additions:
Aliens will now shoot at and destroy base modules if left unchecked. fully destroyed base modules will be removed from the base at the end of battle. any facilities that become disconnected from the access lift will also be destroyed. any destroyed modules will have their contents destroyed as well, not including personnel.
for map makers: for a facility to be considered "destructible" by the engine, it must have an "object" on the top floor whose MCD has byte 60 set.
go here for more information on what this means if you're unsure.
Range Based Accuracy has been renamed to UFO Extender Accuracy, and has been brought back in-line with the original method. the major difference is that i've set the values on a per-weapon basis rather than a global variable for all weapons. i've also expanded on this a little to provide a "minimum effective distance" that works much the same way, except in reverse: the closer the target beyond the minimum range, the higher the accuracy penalty.
the minimum and aimed shot ranges will come into effect regardless of whether the setting is enabled. by default these ranges are 0 and 200 respectively, so with default settings, nothing will change, but should you decide to add a modded item that DOES have these defined as real values, you will get the intended effect. (i have sniper rifles and shotguns in mind)
if you're having trouble understanding exactly what all these numbers mean, UFO extender accuracy comes with a real-time accuracy display on your aiming cursor, so you can easily get an idea of the in-game effects.