Glad you're practicing....
Having stock artwork to work with that someone else has created for you is really handy for practice, but I rarely ever give someone much in the way of a high score for making something out of someone else's hard work. This flash was... to say the least, boring.. It was the same 5 seconds repeated some 500 times.. Robot walks on screen, player robot kills robot.. lather rinse repeat etc.
If you want to impress anyone on NG, you should draw the characters yourself, and go ahead and give a little more thought to making them actual characters. You will draw a lot more viewers in with a story than you will with masses of unnecessary and directionless violence.
Keep practicing. Your explosions at least showed some effort, so props for those.