Version 26.12.2017. Remake of Stx3's Hardcorio:SC2. Hardcorio:SC2 turns Factorio into a hardcore survival game, by completely replacing the enemies, combat mechanics and added life support requirements.
The "Observer" allows purple blobs to be shot by turrets (which also need normal radars) within a certain distance from the observer (which I think is about 16 squares in each direction).
If you mean the squiggly flying bomb scorpions being dropped from the overlords, they can be shot by just normal 5.56 turrets. You just need something that fires a lot of shots per second since there are so many of them.