HALO 2 (2004)
What ending? Oh, you mean this?
This "ending" may not be the most confusing or bizarre in our hobby's history, but it's definitely the most insulting. After a mere four to six hours of play, half of which didn't even feature the character fans paid to see, one of the most highly anticipated games of all time simply stopped. No closure. No explanation. Just a slammed door and a sign reading, "You want more? Buy the sequel."
Three years and $60 later, we finally got some answers. Sort of.