Well, I'm gonna go way back to the SNES-era and mention "Jurassic Park". Me and my brothers rented this game several times because we never managed to complete it. For those who never played it, all you do is basically collecting 18 dinosaur eggs as well as completing several objectives along the way. You couldn't save or anything so you had to complete it on a single playthrough.
We finally did complete the game eventually only to be "rewarded" with a 10 second cutscene of the island being zoomed out with this giant Jurassic Park logo on it. Then a message appeared: Thanks for playing this game (or something like that).
Sure, it's just a SNES game but all those hours spent on it only to get that shitty ending felt terrible and I consider that "Worst ending ever".
