2. Half-Life 2: Episode 3
It's been 5 and a half years since Half Life 2: Episode 2 was released and left fans on an urgent cliffhanger, with Alyx cradling her father's body while Gordon looked on in disbelief. Cruelly, little has ever been said about the development of Episode 3, such that we're all left in the lurch essentially, unsure if Episode 3 will ever actually happen, or if Valve are moving forward with Half-Life 3, or just not bothering with either. Gabe Newell hasn't helped clarify things either, insisting that these episodes are essentially Half-Life 3, just in episodic form so players don't have to wait years to play the game. The problem, ironically, is that we've been waiting long enough that most studios would easily have been able to develop a AAA-title in this time. Though it has always been assumed that the game
would come out eventually, I grow increasingly less optimistic with each passing year.