Hi I have a few questions:
I have a reduced difficulty mod on the mod.io platform which should work with version L10.3 (but dunno about version M). Its called "Nerfed".
But yeah the Eridian Terror missions are supposed to really bite you, hence the 2000 points penalty if you dont go to them. I suggest going to the missions wearing as many Heavy Suit / Power Armor as possible and kill as many enemies as you feel comfortable with, and then Abort. You will get like -800 points or something nasty like that but thats a full 1200 points better than not going, and if you do fine at everything else this probably wont bother you much.
These armor options should prevent most of what the snakemen shoot at you. And if you want to Abort I suggest doing it before the map totally fogs up from the gas munitions. There will be Chrysallids in the fog.
The Motion Scanner (Aye Phone/Dog) functionality was always a nod to the Motion Tracker in the "Aliens" movies. To show only unfriendly units wait until the start of a new turn and do not move any of your units. Pull out your Aye-Phones and check them, all motion blobs are NPCs either badguys or civilians.
This is balanced because it provides you a return on whether there is any Movement going on in a given map area where you may be wondering if it had been cleared or not.
Oddly it doesn't register Berserking units which are opening fire but not actually moving laterally.
It also does not show Vertical orientation which is a nod to the original "Alien" movie where the captain was killed because of misjudging which floor the Alien was actually on. This can be a real pain on Mansion Robbery missions but at least you can know if there's enemy units there (who could even be in the basement).
The burnout times for the handheld shields are a game balance thingy to encourage using the Armor versions which require wearing a dedicated suit. But the Armor versions regenerate.
One goal of the game is to get you to finish missions very fast - within 8 Turns - so if it takes longer than that (a bughunt) you actually lose more than just handheld shields. You lose some of the Glamour rewards too because Glamour is a map item which often has fuse timers as well.