Heartwarming: King's Quest VII: The Princeless Bride
In Episode IV, rescuing the cat.
In Episode VI, Rosella giving the Extra Life to save Edgar.
Valanice reuniting the Tsepishes and later Attis and his wife Ceres in Episode V.
And in the same vein, in the final episode we have Valanice finally finding Rosella, and Edgar being reunited with his long-lost parents, Oberon and Titania.
Rosella giving the spark to the crystal dragon in Episode II, which restores her fire-breathing and her will to live. Seeing her soaring happily through the sky is enough to put a smile on the sourest of faces.