Real talk: fukk that ending. Damn near killed my spirit as a kid, and ruined the entire series for me. How the fukk you gonna kill off EVERYBODY.
As for Alf, if I remember correctly the last episode ended with a cliffhanger - it was either him having to go back to his home planet or him getting caught by authorities....I forget which. All I remember was him standing outside with a bright light around him
Speaking of depressing show endings, I'm about to Google Quantum Leap. Last I remember, the last episode had Al finally return to his family but Sam was still stuck 'leaping', possibly forever. Hopefully I remembered wrong.