What, in your opinion, is, among all of the games (And what the hell; animes too.) that you've ever played, was the single most devastating event in the entire course of the game? I can name a few things.
1) Ultima 7 P2: Serpent Isle. You release the banes. They escape Batlin's control, and take over your three companions, and they separate, and go out to destroy fully ninety percent of the entire land's population. That's right. 90% of everyone you've ever spoken with is now lying dead in the streets of the three major cities and Sleeping Bull Inn, with litter, blood, and ashes lying all over. Complete and utter decimation. You seek out in utter desperation any living soul that went untouched. You pass by the occasional devious horror left behind by one of the Banes. A wise man's tongue cut out. The most beautiful queen in the lands skinned alive and left in the swamps to wander around forever in sheer gruesome horror.
2) Guild Wars: Prophecies. (AKA the first Guild Wars released.) There are two main "time periods" here. The first is the Pre-Searing character tutorial-like world. Everything is absolutely gorgeous. It goes from This to This, once you depart on a mission. Two years later, the entire region (Basically EVERYWHERE) that you explored Pre-Searing, now looks like that. It's absolutely dreadful. There's nothing green ANYWHERE. It's so depressingly sad to see. 😞 I was practically jumping for freaking joy when I got to Kryta where things grew. Plants. Things that give off oxygen instead of freaking carbon dioxide. God....
3) It's more of a gradual change, and much less surprising, as you're obviously in quite a lot of control over it, but in Warcraft III, how you, as the Undead Scourge, (During those campaigns, of course.) laid waste to much of the entire Lordaeron regions and beyond. Heheh. Awesome.
4) Deus Ex: This is actually not a particular event, but the differences between the game and its sequel. In the beginning of Deus Ex Machinae, you arrive on Liberty Island on New York, pretty much right in the shadows of the Statue Of Liberty. Pretty amazing sight, actually. You ascend the base of the statue during that mission to complete it. In Invisible War, the sequel,... ... Well, I'll use spoiler tags.[spoiler]You eventually arrive back at Liberty Island during the last mission. The entire area is composed of snow, glaciers, and cliffs that weren't previously there. the status has been replaced by a hologram, glowing an ominous blue in the moonlight. Even the UNATCO Headquarters that were there are in ruins, and are now inhabited by the occasional bum seeking the barest traces of warmth which may still be found there. It brings back such incredible memories of your first mission in Deus Ex.[/spoiler] ... Yep.

