( Why do I like more the preview?)

I can dig it, I was expecting a ship of sorts from the preview.

I was planning on animating it actually, but ended up not as I already had trouble with a bit of the lighting.

I of course like this one. It would have been cool to see it animated. ~

 Nice design.

Reminds me of Journey as well. This is wonderful!

Reminds me of Journey =)

I like.

this is actually a pretty cool design!

Thank you for the critique. And it's not a preview really, I've seen entries with previews that are just the sprites that we were given to work with (which I honestly think is a misdemeanor of the word preview). I'll take what you said into account though!

First off, I like the sprite a lot and it fits the challenge nicely.  The middle object's glow shouldn't hit the bottom of the cape.  The upper bits could use some work.. they read a little flat.  You have one more color to work with, maybe introduce a hue shift of your blue for the glow and the flat spot.

Also, maybe rethink the preview..I was expecting animation or something.  I suggest using your entry as the preview.