Alien Attack
I can't remember the first part very well but I'll do my best.

I'm in some building with a group of people. I'm sitting by a window looking up at the night sky. I see a light moving, and it's descending to earth. as it gets closer I can tell that it's some kind of ship. It continues to fly down, then lands in the street outside.
It looks kind of like some futuristic police car.

I'm not really sure what it is. I think, it may be some secret government vehicle. I tell other people near by about what I see outside. I don't remember much about what happens next. but there is a normal looking man that comes from the ship. And enters the building. After a while it becomes apparent to me that he is some kind of hostile alien.

He is somehow subtly taking over the minds of the other people in the building. The next thing I remember clearly is that I'm running down corridors trying to get away.
At some point all the doors of the building have been locked, to trap us all in.

I'm running and turning down different corridors trying to lose the alien. I see a door leading outside. I know it's locked, but I slam into it as hard as I can, and the door bursts open. I run out into the street. I see someone standing in the street. It is someone that started out human but had been transformed into an alien.

It attacks me. It has this long elastic slimy rubbery arm that stretches across the distance. it wraps itself around me, and starts to pull me back to the the thing. It has these sticky suction grabbers, that has me stuck. I'm able to force myself out of it. but instantly it grabs onto me again. I grab onto the tentacle arm and pull with all my strength, and I am able to get away. I remember hearing the thing saying something like. you humans would be better off all dying on your own than suffer the fate, we have in store for you. And the thing does not look human at all now.

I run for help. I now notice that all the people near by are just props set up by the alien to make it seem like all is normal if we were to have looked outside.

I end up running back around the side of the building I escaped from. I see a group of people sitting outside. I am afraid that these may have been transformed as well. So I try not to get to close.

Across the street, I see this thing that looks like a huge satellite dish. it is firing this energy beam into space. (This is hard to describe because there is a complex plan here by the alien that I'm having a hard time remembering how it goes exactly.)
The energy beam is trying to make some kind of connection to the aliens home world.
And when the alien connects with this other thing, through the energy beam. it will come into it's full power. And it will be the end of all humanity.(That's the simple version)

I run across the street,and leap into the dish of the satellite. There are these light bulb looking things in the dish, that are sending the energy into space. I have some kind of metal rod in my hand now. And I begin smashing the light bulbs, trying to destroy the beam.

But as I destroy this one, I see another bigger satellite rise up out of the ground not too far away. The dish itself is to high for me to climb into. And I hear the alien say something like. That there is no way I can make it into this dish. And I don't have the guts to try for it.

There is a wall near me. I jump up onto the wall. I see what the alien means. The dish is quite high in the air. I have to make quite a jump from the wall in order to make it. if I don't make it I will fall a long way to the ground. But I'm not deterred!

I run along the top of the wall as fast as I can. When I get to the end, I leap into the air, tuck into a ball, then I just make it into the dish. I roll down the inside edge of the bowl shape. I hear the alien scream in protest. The next thing I know, the alien is up in the dish with me trying to stop me. But, I try to ignore it. And I begin smashing my metal rod into these light bulb things. They don't break easy. but with a few determined hard hits they break.

With every one I disable, a hear the alien scream. I look up, and I can see that the alien is beginning to grow week, and starting to wither. I continue my work as I wake up.