I think that my worst expreiences are probably
Karnov for the original NES. It just says: Congratulations. Then goes right back to the title screen. And that game was dam hard too....grrr....
Or from a more modern perspective, Bioshock.
You have to play for a long time, and play through this incredibly story-driven game, which relies heavily on voice acting, character development, and a pretty crazy plot-line, then you beat the game, the ending is about 20 seconds long, then IT GOES RIGHT BACK TO THE DAMN TITLE SCREEN!
WTF is UP, game developers? Who conviced them they could EVER get away with that crap?
On the flipside, I think FF III for the SNES probably had the greatest ending. It was 30 minutes long -- very satisfying.....
I mean, you just beat the guy and then some stupid little cutscene depending on what you did with the little sisters and then go to the title screen. ****, the credits didn't even roll.
Have you guys ever played Ghost Busters for Nintendo, even if you did you probably never got to the end and you never want to. It has the absolute worst ending in the world.
I must say NSMB. I mean, Mario/Luigi saves the princess from Bowser. Then she kisses him. Then you look at an album. Then you see Bowser Jr. dragging on Bowser. I mean, WTF? Kidnapping the princess goes only for Mario games, but those endings was only good until the early 90s! COME ON.
In Assassins Creed when you do all of this repetitive stuff just to stare at a wall with hieroglyphics on it and get credits!? I mean WTF Ubisoft? That has to be one of the worst next gen game endings I have ever witnessed all because it isn't ending an ending!