Quite nice. The explosion animations are great. Like you said, the ship should pop out more, I've provided an edit for some ideas:
[STEP 0]
-optimized the pallete
-merged several of the dark tones (like 5 or so O_o) and several of the lighter tones (too close together)
-contrasted the remaining colors
-working with fewer colors tends to make a pic much more contrasted
-the optimization tends to really...fsk up the look of the ship at first heh...eh...ew
[STEP 1]
-deblurred the cockpit area
-deblurred tail of ship, also gave it a more oval shape (lopsided towards the back end)
-contrasted the two 'lines' right above it
[STEP 2]
-cleaned wings up by 'flattened' the wings using 3 or so tones, I did this to prep for detail
-elliminated darkest color
[STEP 3]
-decided to make the wing-edge and the center represent the major wing details
(when designing small objects you must decide which details should stand out and which don't, or stand out alot less. This variation is easier on the eyes, and helps guide the viewer through your sprite)
-extruded the edge a bit for a tiny bit of extra detail
[STEP 4]
-decided to mute the other wing details
-made the inner portion of the wing stand out a bit
-contrasted the inner portion of the wing detail by removing one of the lighter tones
-reworked the detail on the wing engines/boosters/cylindrical objects XD
[STEP 5]
-detailed the main engine a bit more
-had to modify the back portion a bit to allow for more detail in the engine
-decided to merge the are where the wings connect to the ship's body
[STEP 6]
here I just pretty much fondled the whole design to my own sick and perveted tastes, (just use this last one for inspiration on other designs I guess or trash it XD)