I love this game, but sometimes it just really rolls the dice against you, especially on Harder and up. I once was having a really good playthrough and then it's one turn before the horde was on my doorstep. So I have my defenses ready, and then there's a random encounter that completely obliterates me when I had 15% chance of failure.
Then the horde is at my door and 89% chance of utter death.
I guess this game is a game for unlucky bastards.