Depends upon what you mean by "ending".  Most all classic games, even when you reached the end, allowed you to continue play.  However a few of them did have a final level that was different from the main game, i.e. a boss battle.  Phoenix has that, as does Gorf.  I think that phoenix's release beat gorfs by a few months, but I'm guessing they were both in development at the time. 
So yeah, Phoenix.