Starcraft in my opinion is the greatest Real Time Strategy (RTS) game of all time. SC2 was an improvement upon the theme but without the success of original StarCraft, the 2nd one never would have been made. That's why I rank it higher even though the 2nd installment is in fact a better game.
There is very important part of the StarCraft story where one of the human characters named Sarah Kerrigan ends up getting taken over by the evil Zerg forces. This was a very well done part of the story and when Kerrigan ends up coming back into the story she is now one of the baddies. Prior to that she was a rather important part of the human campaign and I thought it was a really inventive thing they did there. By the time she is captured she was probably your favorite character in the game. If you were playing it for the first time she is presumed killed.
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When she returns after having her mind taken over by the Zerg Hivemind, she remains one of your favorite characters because as a baddie, she is even more awesome than she was as a ally.
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The mission where Kerrigan gets overrun by the Zerg is one that people probably remember the most in the entire StarCraft 1 story. You start out with a base that is being threatened by the Zerg to the north and you have to defend that end while venturing out to take over the Protoss bases that are on the same map. If you try to enter the Zerg territory to the north and east the game reminds you to not try to do that because it can't be done or something like that.
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Normally people will end up forming some sort of defense that includes bunkers and siege tanks to defend against the never ending forces to the north and this actually isn't that difficult to pull off. After you perform your objectives against the Protoss on the level, it triggers an event where all remaining forces in the area to the north to attack all at once and then overrun Kerrigan's position.
While I am certainly not the only person that has ever done this, I decided to one day completely take out the Zerg rush that happens at the end of the mission and while it wasn't easy, it is certainly possible!
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There's a nice map someone made of the entire map for Terran mission number 9. The Zerg base doesn't look so daunting in this map but the reason why it is so difficult to take over is because it is surrounded by turrets that will take out anything flying towards it. One might think that with some decent tactics that you could overrun their base and you would be correct in that.
You could take out the turrets defending the Zerg base but one of the mission objectives that must be obeyed is that you are not allowed to destroy any Zerg buildings. If you do so, the mission fails.
However, you can make this level more interesting by seriously preparing for the Zerg invasion with a rather impenetrable wall of siege tanks, turrets, and battlecruisers. If you have enough of them, even the massive wave of Zerg they send at you all at once will not be enough.
No matter what you do in this mission the zerg will continue to come even if you have wiped out all of their units because they programmed in a spawn point in the Zerg base that endlessly throws Zerg units out of it. I was able to discover this by doing a scan of the base and finding it because you can't walk any troops up there because they will be destroyed by zerg turrets that you are not allowed to destroy. Their units never stop coming. The just spawn over and over out of the same spot on the map and continue to head towards your base even though they get mowed down by 20 siege tank blasts as soon as they appear.
Even if you have enough troops to shut down all of their attacks the mission will still end even though in order for the mission to make sense in the grand scheme of the story, Kerrigan needs to be taken prisoner. It's kind of funny because you are sitting there seeing the Zerg definitely fail at overtaking your base but the game says they did anyway. The story cannot progress without Kerrigan being "captured" even though you can see that she wasn't
If you were just casually playing this game your position would be overrun and it might initially seem unfair because it is supposed to be something that is inevitable. It took a lot of preparation and certainly extended the amount of time that I spent on this map but this is the sort of thing I find entertaining in gaming. Once you know a map you start to do crazy things like this.
There were a couple of "endless spawn points" that happened in SC2 as well and they were located inside of a Protoss base that is meant to be impossible for your to overtake. I will go over that episode in the next installment and explain the little tricks you can use to make it much easier to completely overwhelm the Protoss in that one as well.