Well you've asked for crits, these will be pretty harsh.
First off, I don't think this is one of your better colorings as I think you can do a whole lot better, why? Well, you've been rather inconsistent with the lightsources, especially noticable on Kup and Grimlock which seems to be one panel of the rather confusing set of panels Wildman made there (some people like it that way, but I don't, one of the things I dislike about Wildman's pencils next to them often looking sloppy and unfinished or deformed for a proffesional - see Starscream's face for instance).
If you're going for shiny/glowing eyes, that didn't work out, they're too dark and they're overwhelming the lines a bit.
The sky doesn't quite look like a starfield as I presume your intention was. It looks more like you use a gaussian blurr directly over a noise filter, and just colored the radiant color of the explosion over that in a rather irregular way, especially as the radiant just simply stops instead of fading away. I suggest you look up a starfield tutorial.
http://gallery.artofgregmartin.com/t...tar_field.html This one is the one I use and Josh uses since I handed it to him.
It takes some work but the results are amazing.
The explosion itself needs to be more vivid. It's a little bland at the moment. The smoke and dust seems to be too thick and in my opinion is also a bit too blobby (again, particularly around the edges) rather than dusty.
There seem to be two Swoops in the image rather than one that's transforming. I suggest you fade the lineart or blurr that part of the image such that you feel the suggestion of speed and that there's clearly only one Swoop rather than Swoop and his twin behind him.
I think it was Snarl driving on the right, right? I think you could add in some laser fire from his cannon there.
Lastly, I think you could have made a few better picks for the flat colors, particularly on the tires and tracks on Grimlock, as well as a bit more orangy yellow on Grimmy, though the latter is a personal preference.
Next to that... it's Wildman... that doesn't help it for me either... >.>
Aaaaanyway, sorry for the abundance of crits, but I hope these help you in the future!
I'm just overly critical (which can be a good and a bad thing I think) and have some nice connections to get lineart. 
