Vanilla CDDA has a lot of entertaining endings, proper or not. I tend to find one within the first one or two in-game days. Great game! I like to install it now and then just to marvel at all the new things that have been added and then be killed by not knowing what I am doing.

Never got far enough to interact with most systems in the game or worry about proper endings.

CDDA:BN adds a true 'endgame' objective (story bound) but OFC you are free to do anything you want anytime, eve after 'finishing' the game.