I've been playing Grand Theft Auto III lately, and I recently got to a major point that I totally did not see coming... and I loved it! It changed the entire game and made the story loads better!
It starts with the final mission from Salvatore called "Last Requests". He wants you to go get a car filled with brains and take it to the dump to get the car crushed, removing any evidence. At first, I thought "Is he serious? That's flat-out absurd!" But, I went out to get the mission done, anyway. After I drove for a bit to get to the car he wanted me to get, I received a pager notice... which I ignored, because they always told me something I didn't really care about, like that they just restocked their firearms at Amunation. Big deal, I get firearms all the time. I went to the car, got inside, started the engine, and it blew up. No, seriously... the car exploded and I died. I tried it a second time, thinking it must've been a glitch. Same thing happened. The third time, I decided to have a look at the pager message I was getting. I was being warned that the mission was a trap. Salvatore wants me dead! So, here I was with someone I'd never met, escaping away with them from Salvatore and... unlocking an entire island to explore! Awesome. New cars, new people, new weapons, new gangs, the addition of the FBI on my tail... It both changed the game and thickened the plot.
Plus, my next mission was to kill Salvatore. One of my favorite missions, but also the hardest thus far. There were so many ways it could be done. You have to strategize. The method I ended up going with was zipping past the building Salvatore was in, and heading straight towards his house. When I got to the wall with the little opening for the dirt road that lead there, I began stuffing various cars in there (four or five works well), blocking the entrance. That way, when he'd come, he'd try to slowly push through, giving me the chance to throw a grenade in his face, killing him and all those mafia dudes. Of course, more do come on the way, so it's best to escape down the beach, rather than where you just came from. Yeah. The mafia wants you dead, as well as the Triads. This shocking plot twist made the entire game better for so many reasons!
Then, there's Half-Life. There's something about a specific type of enemy in that game that hit me much harder when I figured it out on my own, rather than the game simply telling me what was going on.
Those zombie-like things are fallen Black Mesa scientists being controlled by headcrabs. I never even thought of such a thing up until one scientist asked "Why are those things wearing science team uniforms?" That's what it hit me. Immediately, my mind began to rush through the different things I had been seeing up to this point. The game had been foreshadowing this for quite some time. I had seen a headcrab lap up and latch itself onto a scientists head, and he collapsed instantly. I saw another downed man leaning against a wall, with a headcrab digging its legs down his neck. Also, the heads of these zombies bore a striking reseblance to the headcrabs. Once I had put all these pieces together as to what I had been fighting thus far, it heat me with much more weight than if something had just told me right from the get go, when I first saw them. Before, I didn't know what I was fighting. Later on, I did. And I didn't fight them quite the same after that.
There have also been a few moments like this is [Prorotype].
I can think of several of these. (I haven't beaten the game just yet, so there may be more. It honestly wouldn't surprise me.) The one that got me the most had to be the first one. It was quite early on in the game. This whole time, all my enemies were simply piss-easy to beat. All these marines and their puny tanks and helicopters meant nothing. They couldn't give me so much as a scratch! Suddenly, Alex fell out of a building that held someone called "Elizabeth Green" in it, and several monsters fell out along with him. Suddenly, I had challenge. Just BOOM! Out of nowhere, the game suddenly spiked in difficulty. Here's there were several hunters that wanted to kill me. There were loads of them. They were everywhere. They were always aware my presence. They were faster than me. And I couldn't kill them. I kept running for my life for a long time. The only thing I had over them was that I was more agile. So, if I kept jumping around from place to place, changing direction and terrain as much as I could, I could keep them away... a little. But once I got the claws... Boo-ya! It's payback time! Other shocking moments include when another, more rare monster called a "Leader" had captured Alix's sister, Dana and got away. Then, there was the time when several of Alex's powers were taken away. There was the point when, after all this time, Dana had no idea that Alex was killing anyone, let alone consuming them or even possessing powers until Alex had made an offhand comment. There was also the point when Blackwatch was introduced. No introductory cutscene, no stolen memory to tell me in advance, no foreshadowing at all to tell me that they were coming (at least, aside from the extremely vague prologue that took place towards the end of the game) in the near future. Just BOOM! There they were... killing people. Just... shooting them. Gunning everyone down like a storm of bullets in a widespread area. Well, that was my shtick. So, I killed 'em all in that area. Did anyone else? There was also this one point right at where I've left off thus far, where Alex is pretending to be working with the Marines and the Blackwatch, and ends up going to a meeting. About a minute or two into it, the guy speaking mentions that they've developed a new gas that was toxic to the infected monsters, but completely safe for humans. So safe, in fact, that they had all been breathing it since they had entered the room. At that moment, Alex started coughing and burst out of the room. His cover blown.
There is one other I can think of. Not sure if it counts. It was right at the very end and was downright hilarious and made me rethink the entire point of everything I just did in Zapper: One Wicked Cricket!
Turns out that this entire time, Zapper didn't go out of his way to rescue his little brother, Zipper because it was the right thing to do, or to stop Maggie the Magpie and have her sent off to jail... He only rescued the little guy, because he wanted his television reception back. And Zipper's antennae made the picture work!