"Escape to Salvation" - "Magnificent Retreat" [Campaign 4, Mission 4]

Hello everyone who had problems completing the final mission.
The aliens only arrive when Zehred has no Thunderers, not from idling. Heroes can be stopped regardless of the computer's level; you just need to switch the hero movement speed. (At 6x speed, you won't be able to stop them, but you don't have to play the entire mission at 1x — just change the speed when the heroes appear). I didn't pay much attention to leveling up heroes; I used "artmoney" for the whole game. And I also broke the final mission — first gold, then Thunderers. And with 999000, I easily took out Frieda.