The fact that I got the "bad ending", but I fully understand why and why it makes literary sense makes this a great game
Ciri doubts herself in the bad ending, because she is so used to Geralt always being there for her. I picked those types of "good dad" options. Since she doubted her self, it lead to her still saving the world, but dying in the process. The cut scene that plays as shes in the ice place confirms this. Its her, on her own, with no Geralt to be her support this time...
Only thing that kinda pisses me of is, I picked the options that led to it because I wanted to see some of the cut scenes as I assumed the more lore/content the better.