Fails:
In my first playthrough, I got all of my unpromoted units killed by chapter 18 (except Natasha). Eirika died once. I accidentally made Duessel commit suicide by Devil Axe and I let Syrene die. I never rescued the villagers in chapters 6 and 17. I'm pretty sure I overused Seth. I also intentionally killed Joshua, Amelia and Rennac (I didn't know how to recruit them!) and never recruited Cormag. I restarted the game and decided to never let anyone die again.
I've never managed to save Duessel's units (NPC cavaliers) in chapter 10 in Ephraim's route.
I haven't beat the hard mode yet (is it called "difficult" in the game? I'm not sure).
Moulder got about 1% critted by a Dracozombie in the tenth floor of Lagdou.
Wins:
Marisa got hit by an axe user. Then, a Bonewalker with a Steel Bow attacked her. Hit was around 45%, she would have died if it hit. But she dodged!
Playing on GBA, I sent Joshua to the arena in chapter 5. He fought against a Shaman whose Hit was around 40%. Joshua dodged an attack which would have killed him and won. I still wonder why I took the chance.
I've sometimes finished Caellach with Knoll, in the Eirika route.
Kyle was about to die and dodged a Pegasus Knight with 70% Hit. I was being stupid, I had him hold a Steel Sword to raise his Sword Level.