XCOM 2

The most difficult trophy is not to pass . The difficulty is that it is unknown where and when the Bosses will appear (except for the quest for Gamma), and that you need to kill the boss with a SHOT in observation mode and precisely on the move where the boss runs away into the portal. And you will have to do it manually, Glitch does not work. Even if you remove the boss's health and then load without the glitch, the boss will open a portal, but will not run into it. The meat grinder doesn’t work either, and you won’t have one unless it’s with the quest colonel in the quest for Gamma.
Now in order:
1) The boss can appear in the most inconvenient mission: either with a timer or in a quest, for example, my Alpha fell on the TV tower (the penultimate battle).
2) It is necessary to kill by OBSERVATION and precisely in motion. Simply killing after opening a portal or killing while moving when the boss does not reach the portal will NOT give you the trophy!
3) Forget about the glitch right away, just one move of the boss under the glitch is enough and the shipment will be ruined after that - the boss will not go into the portal.
Now the tips:
1) The easiest way to do it is on Beta (Berserker), he only has a contact attack and you can hide from him on the roof of the third floor (he penetrates the second, although not much). Block or blow up lifts and ladders and he won't reach you.
2) Use special grenades: acid and incendiary grenades are especially good; poison grenades do not affect Gamma. Freezing will simply give you a win per turn. Grenades should be given to grenade launchers in the last slot with pumping for 2 grenades, then you will have 2 special grenades, even if there is only one available. The grenade must be thrown so that the boss is in the center of the explosion, then he WILL NOT MOVE (but will shoot, Alpha can fly out) until the acid or fire around disappears (with the exception of an open gate - then he will break through).
3) Use Arrow Launcher and Ax (direct attack) - a high chance of stunning the boss. Throwing an ax and the ability to shoot a pistol without spending a move do not cause the boss to move.
4) If necessary (soldiers are left without ammunition or without an effective move), make a turn transition ahead of schedule - using the tablet button.
5) Sometimes it is possible to block the boss’s movement towards the portal, and he will not be able to reach it in one turn. This will give you the opportunity to put the soldier on OBSERVATION, but you cannot kill the boss during this turn.
6) Killing with a meat grinder while escaping or from acid-fire does NOT give you a trophy.

The most difficult and missable trophy of all the DLCs.
There are only three rulers. I will describe my tactics using the example of a berserker ruler.
1. We have a ranger in the squad with the “meat grinder” perk. We surround the “boar” and reduce life to a minimum, but so that there is enough left for a shot and he does not die! The ranger's position is not far from the target (if there are two rangers, then on opposite sides, it is not known where he will go). During this procedure we use a glitch for endless moves. After each of your moves, transfer your move by pressing the touchpad. And so, there was only one life left to shoot. Let's save.
2. We leave the game. Close the application. This is necessary to reset the glitch.
3. Let's launch. Loading the save. Our move. We shoot, but not with the ranger. The berserker will open a rift and try to escape. And here it all depends on luck. If he runs next to your ranger, he will receive a fatal blow from the sword. If it doesn't work, reboot. I hope I made it clear.
PS You can try without glitch. But then the squad is all colonels and in cool armor. The battle will not be easy.