A decent space invaders clone. Going to second Gumball's comment on the movement... as I recall one of the key strategies in Space Invaders was trimming invaders off the sides to slow down how quickly they advance. I also think there was a greater limit on the number of shots in flight, so there was much more incentive to not miss, otherwise you had to wait for your next shot. In your game I could just hold down shoot and move around dodging incoming fire, so it was more about dodging than shooting.
The special attack was an awesome surprise - really liked that!
Here's my scores:
