Hm... Usually game over sets in when all party members are dead. Could be my mistake as well.
And that bug IS a serious issue. >.> Everything that causes a crash is a serious issue to me. I think I know what the problem is. The bug in the earlier version happened when two enemies got within range and could see each other. If 2 leaders have that problem, I know what the cause is.
You see, the technical detail here is that each leader has an array of minions and each other enemy can have a leader assigned. The problem most probably happens when a leader tries to add the other leader to his minion array. Then he calls the same method for the other leader. Now, when the other leader adds the first leader to his array and calls his method again, there is a "Stack level too deep" error as RGSS Ruby doesn't allow recursion. Even if it would, this would end up freezing the game as there is no "exit condition" of this recursion. I'll be sure to fix this. I don't use leaders yet and even if I do, I use only one when testing Blizz-ABS, so I wasn't likely to find that bug myself.