Well, don't get me wrong... but they are boring.
Try adding more colors.
It can be grayscale, but right now they just look like... letters.

Maybe if you use some symbolism, your creations can go a little higher.
Like this cup. And then make a game about breakfast. I don't know.

I made these new clouds a little while, thanks for the feedback I have just received from you!



I'll do more edits based in your feedback

Wow, i actually got your concept completely wrong, you're doing a horizon from the ground!
My bad.
And the clouds got a really good improvement, nice!

~edit~
So here are my 2 cents, maybe you're trying to take a picture from your idea in a way too large scale, keeping it smaller and tight will make things to come together more easily.
Also, im not quite sure what you're trying to achieve with that gradient, are those mountains? Is that the sky? Anyways, heres what im trying to say:

I mean, you can always use real pictures as reference, you know?
Heres one i quickly pixelated using secret tools

See how you did it inverted? Maybe that's whats bothering you.

Im no expert, but as far as im concerned, just adding more frames would make it look a lot better.
Really, single high contrasted pixels with a lot of frames creates a good impression of "sparks"

To prove my point:
http://37.media.tumblr.com/6650c141f8b4247867a9b4b91b37829b/tumblr_n4nfnyQWJs1smtro9o1_1280.gif
This is from a kickstarter project called witchmarsch