i think i had a epileptic seziure. Ok so for some improvment words, try when resizing a render to hold shift when using the transformation tool, also only resize it from the top left, right or bottom right or bottom left hand corner, remember always use shift if not your render will look grainy when resized and the porportions of the render are off and give a slight "squished look" like your darthvader one, i would really like to see your graphics with out huge multiply different types of text that flash all sorts of crazy colors, it takes away from the apeal. try using only one text type and dont make it so large, the text in my sig is a perfect example not what to do, you have to have a text that flows with the sig not just any type of text, im to lazy to fix mine right now so im keeping it as it is. also try blending your renders in a bit more to the back grounds, its hard to see what your back grounds look like with the clutter of the text and animations, if your going to do animations make it subtle not crazy.
Also when doing the test images please do not use animation, you can if you want but if it doesnt look good, it can be a detering factor in a decision to accept your app of not.