I understand that you invested a significant amount of time and energy into this, but still it seems a really boring piece to me.
It can be a nice background for some real picture, but the picture is missing there for me.
At least the mentioned caravan, a zeppelin, a sun, sandworm in the foreground .. anything to give the image some meaning would be great imho.

yeah, a camel caravan would be great- sandwyrms, even better! still it's prinny sexy.

Where's the sand worms?

You used Paint to draw it, and GIF Movie Gear to finish it . . . you wretched Photoshop deprived people you!

I checked the WIP out. :)

As for now, this will prolly get my vote ;)

Yes, and I think I have even got some earlier WIP than the one in the thread. 

check the challenge thread, i believe he posted a wip there.

OK. I'm not saying that the picture is a color reduction but the palette and use of colors seems a little strange in places.

I used MS Paint to draw it, and then Gif Movie Gear to make it transparent GIF. 

Good timing, I started to read Paul of Dune a couple of days ago and this reminds me pretty much of Arrakis.

You could improve the dithering in this pretty much to get a softer fade between the colors, otherwise I don't really have any crits. I like the mood in the picture and it's pretty original.

I think pictures like this stay in the queue a while because people here tend to be pretty sceptical towards stuff that they self can't make easily or doesn't look like random videogame sprites. (this don't seem to be a problem if you are a well known name here) Yeah, everybody can flame me but that statement is based on observations.

Edit:

I took a closer look at the picture now I'm a little more sceptical now. The palette and usage of colors looks a bit suspicious, like if the picture is a color reduction with pixels placed by hand after...

Please tell what tools you used making this, and tell a bit more of the process of making it.

Why this is being so long in the queue? I saw similiar thing getting through with few hours and this has been here whole day already. 

Looks really good, but the scene is a little boring for my taste. I would love to see some silhouettes of a camel caravan or something. Still great :)

I tried, but it didn't look so good with less colors.

where's all the colours gone?

I see like, 10 max..

Looks nice though,. just maybe try and cut down on the colour amount?