Final Level: The Great Journey
Why It Sucked: Bungie's first mistake was forcing fans to play half the game as The Arbiter, an alien, enemy soldier who would have been nothing but target practice for the Master Chief in the first Halo. To top it off, the Chief's storyline ends on a cliffhanger at the end of the second-to-last level, and the finale is an Arbiter level. Seriously?
How We Would End It: With an extra mission after The Great Journey that resolved the Chief's arc instead of leaving him (and fans) hanging for three fucking years.