Righty-o, time for that big fat reply i promised you yesterday.
*Clears throat*
Your first attempt at pixel art is surprisingly good, way better than my first attempt. Needless to say though, it's not good overall. Shading's off and all that, but you probably know that already, seeing that you've made better stuff later on.
The car is probably the one i like best, as it's fairly detailed and also shaded decently. That's not to say that it couldn't be better, though. The shape of a car can roughly be described as a rounded, volumetric trapezoid, and your shading doesn't give that impression. The wheels appear to be floating in the air, just below the car, but i see that this is just an illusion caused by the bright background. Nevertheless, this illusion should be avoided, which can be done with some shading and a couple of pixels of outline. There are also some redundant black outlines, but really, i'd rather see too much outlining than too little. So instead of removing them, make them a dark shade of whatever color is nearest, like red.
Once again i feel obliged to show you how it
could be done. Because i'm just an idiot like that.
Before:
After:
(Couldn't be assed to add transparency)
Probably didn't get all the small details right, but still. When i copied the image, it gave me a black background, so i had to redo the outline. :I
You should also take into consideration which parts of the car are shadowed by the other parts, to give it a more realistic appearance. Also, needs moar headlight. =P
Now for the animation... It's pretty good, but awfully slow. When i first saw it in your avatar, i thought it was standing still. :U
My only suggestions would be to speed it up, and also remove that gianormous white background. Y'know, just crop it away.
The building is fine, no real complaints here. Apart from the striped walls. Should be more bricky/concretey/whatever. Living in such a striped house must be bad for your psyche. :V
Also, very nice texture on the roof, i consistently fail when doing textures.
And finally, the army of pixels. It looks good, and i like how you made it a 3/4th view instead of frontal or side view. However, their torsoes seem awfully flat. A human torso is more or less like a wide cylinder, and should be shaded as such. Also, the arm that's closest to the viewer doesn't stand out enough, especially on the yellow and green guys. You can fix this by making a dark line where the arm and torso overlap each other. Couple this with some shading, and it quickly becomes crystal clear. Another little thing would be the apparent lack of skin color, but this isn't a biggie. I originally thought that they were white as a sheet, but a closer look reveals a very bright skin tone. You should make it a bit darker, so people won't think that you've drawn ghosts. :I
Also, clothes generally don't produce speculars/highlights, so there's no need to make them.
Oh yeah, final note, when shading, also keep in mind that the head is a big lump on top of their shoulders, so it's naturally going to cast a shadow.
And because i'm bored (and still just an idiot like that), i tried fixing up your guys. :U
All in all, i say good job.