Portal 2
After writing this piece, I was pretty disgusted with how it was nothing but unadulterated praise and sunshine glee for Portal 2. So I decided to go back in and put in a negative depressing image for every positive thing I said.
Given that I've finished Portal 2 five times (4 on PC, 1 on Xbox), I'm not going to use a score chart, because it would just be 20 out of 10 the whole way. That's not to say there aren't any issues with the game, just that the strength of the atmosphere, gameplay, story, dialogue and characters overshadow any other problems.

I followed the game closely before its launch, so I watched the ending of the ARG and all its associated drama. It was hilarious to me that gamers were so offended by Valve and other developer's efforts in building this entire experience because it was 'only' released 10 hours early, and people who chose to follow guides and get all 36 of the virtual potato collectibles were 'only' rewarded with a free $100 game pack, and above all, how the entire thing was an evil corporate move to force people to buy indie games.
This anger seemed to pass onto the game itself; in the beginning, critical reviews were amazing but user reviews were awful, and it was all from PC gamers. There were three points people kept harping on: 1) Including cosmetic hats for real life money is a sin comparable to at least three major wars, 2) When saving the game on the PC version, it refers to 'not turning off your console', proving the entire game is just a console port and thus a complete piece of shit, and 3) The game is only 15 minutes long. Now that it's been a while, anger seems to have simmered down into just one point: the game is stupidly simple with no challenge and is made for console morons. PC gamers are a great bunch, aren't they?
My first playthrough was about 10 hours. I got stuck quite a few times, especially in the end, and I never felt like it was because the game was being unfair, it was always because I wasn't understanding something. I never spent so long on a puzzle that I gave up and looked up hints. In short, the puzzle and gameplay aspect was perfect for me, and I think most people feel the same way.

It's impossible to put into words how well designed the story and characters are, or how well written the dialogue is. This has always been the real appeal of Portal; anyone playing solely for the gameplay would invariably get bored after the 10th hour of shooting portals for no overall purpose. The game is designed for people to play through at least a couple times; you just can't do or see everything the first time without missing part of the experience of just playing it naturally. And with all the alternate and optional dialogue in the game (especially the ending), playing this incredibly linear game twice isn't as fatiguing as you think.

Doing a followup to Portal is pretty much a death sentence. The game is so beloved among gamers, it's almost fashionable to hate it and all the memes it's created. Doing an actual sequel makes you responsible for delivering to people's impossible expectations. They not only want the feeling they got playing Portal 1 for the first time, but they want something better. It's insane that Valve delivered this; they were able to revisit aspects of the first game without treading on tired ideas, and they were able to expand the experience and universe tenfold into something truly amazing.

The ending is probably what stands out the most, since they're so hard to do well. Portal has always been an absurd game set in an absurd universe with a backdrop of serious depth; subtly dealing with loneliness, acceptance, will and morality. The last 5 minutes of the game embraces all of this in every way, which is what makes it one of the best video game endings of all time.

And in case you're wondering, my five playthroughs weren't all just because I am stupidly obsessed with the game...they all had a purpose.
- Initial playthrough, in which I missed pretty much every single secret.
- Playthrough listening to the developer commentary.
- Playthrough looking for every single secret and exploring every nook and cranny.
- Playthrough on the Xbox, getting every single player achievement.
- Playthrough with noclipping, trying to find secrets...I found none, but the level design was fascinating.

