If you want to beat the boss Click Start random mission and put all the enemies on the top tower cuz the observer spawns in the top tower and after all the enemies dead you get the flying and the reality crusher but dont press the delete button cuz it can make delete him and wont get the achievement and grab him and find all rhe blueprints on the map
The boss itself isn't really hard, but rather a little difficult, since your "fighting" a nextbot (a nextbot is a 3d png that chases you anywhere you are), you'll get the hang of it if you keep trying
Heres a more ez one: go to the gore doll that spawns on the big tower then make him very small then put him between the yellow and blue crate you could put armor on him its your choice anyways just spawn the boss and it should target the small guy just becareful when getting the blueprint at the crate place (do this fast before patchhh!!)
Guys I beat it not because of this I got goredoll made him tiny and put him in logs so observer try to get him but he can't so he gets stuck edit) also do it before the boss fight then you activate the boss fight