To avoid confusion, disappointing does not mean bad. They are just games you had high hopes for but they didn't quite meet them. You can just make a simple list or explain each one, it's up to you. And there's no limit to how many games you can list.

My Best:
5. Spec-Ops: The Line
Ever played a game that had a story so powerful, it felt like it just punched you in the gut? Spec-Ops: The Line did just that, except it proceed to continuously kick me while I was metaphorically on the ground...in a good way. Spec-Ops story was something that I NEVER expected. I thought I was going to play a boring CoD clone, but...wow. Some of the most mature writing I have ever seen in a game, Spec-Ops story preps you up and knocks you down in ways I have never seen in a game before. The characters, the narrative, the subtly, the themes; all of it was glorious in a completely sickening way. This game made me feel genuine sickness, guilt, and depression. Not a game for the feint of heart or the simple of mind. This would be higher on my list but admittedly the game is very short and the multiplayer is just unnecessary; it ruins the game's overall message.

4. XCOM: Enemy Unknown
A reboot of an older series, XCOM proves to the industry that every reboot of an old series doesn't have to be a generic shooter (I'm looking at you, Syndicate and EA). While providing organic combat situations and strategy, it keeps it's roots in turn based strategy firmly attached. A fantastic game that combines a steady flow of action and pacing with a deep turn based system that allows for unconventional strategy is a win in my book.

3. Dishonored
A new and much needed IP in this generation of sequels, Dishonored's refreshingly deep stealth gameplay is a fantastic step away from what's on the market right now. A wide variety of combat and stealth options with vast and expansive levels, combined with a oily/steam-punk aesthetic makes this game a marvel to me. Sure it's a bit short, but I really didn't notice the length when I replayed the game 4 times to try out different options and routes.

2. The Walking Dead: The Game
Another game with a gripping story. TWD revitalized point and click adventure games of old and commercialized on episodic game publishing. With fantastic characters, a deep a sprawling narrative where choices matter, and an incredible ending to end the game on, TWD is certainly an achievement.

1. Borderlands 2
I turned my brain off for this one, and I am really glad I did. Borderlands 2 was by far the game I had the most fun out of, and funnily enough, I played it completely alone the first time. Did a co-op run after that, then did two characters up to level 50 and I'm STILL playing it! The game, in my opinion, is just downright hilarious. A few lines and characters are a miss, such as the memes, but I found myself laughing more than any game has ever made made me. This game took everything people liked about the first and improved them ten-fold. On top of having one of the best villains in recent memory, this game was everything I had hoped it would be and them some.

Honorable Mentions:
-Spiral Knights: Found this game a few weeks ago and have been addicted since.
-Journey
-Far Cry 3

Games that disappointed me:
-Mass Effect 3
Sorry Bioware, even though you "fixed" the ending, this game was a scar I will not soon forget. Don't let EA rush you next time, write your stories with the quality you used to have and I know you still have. That and make the game an RPG like Mass Effect 1 again.

-Assassins Creed 3
What happened to being an assassin in Assassins Creed? With the staggering amount of side content that distract from the gameplay I bought the game for, I can't help but feel your stagnating your franchise. Sorry Assassins Creed, it's been fun, but if you want me back, figure out your roots and improve on that. Do not add skinner-box game mechanics to make me think I'm enjoying your game.