I am no expert on this game. I play on rookie and enjoy the game till the difficulty ramps up too fast. It is obvious that this has been an ongoing problem as I see nerfs to some of these points as I come back to the game after a few months. You have difficulty settings so that if someone wants to constantly restart missions and bang their head against a wall they can but I don’t find that fun. Currently it’s the Scyllas. There is no way at my current level I have any hope of beating it. I have 6 dead soldiers and maybe take 5% of it’s life. Before this per my own experience and comments in this forum it was Acid, then Sirens, then multiple Chirons that took so long to kill the game got boring. Do you ever learn? You fixed these other problems then throw another one out there. Again you have difficulty settings so if someone likes this type of game they can have it. I don’t mind restarting some missions and rethinking my strategy but not having any chance at all???
I had similar issues as you, however I have found a way to take out the Scyllas in their citadel, you will notice that they can not pass through the arched doors! This means you can sit just behind it and shoot the crap out of it. However, there are a few things to be aware of: 1: There is ALWAYS a spawn point behind you in this area, so you need to station one or two men on it permanently with over watch, this will prevent any nastiest from spawning. 2: everything else can come through the front door, so it is not a turkey shoot! 3: You may have to venture out to encourage it to come to you, I like to send some spider mines to stir it up. But if you get yourself in that safe house you can eventually take it out! You can also paralyze it quite well from here as well, but it does have a habit of blocking the door so you can’t get out until you kill it, that is quite annoying! Anyway give that a try and you will not have even one dead man…