Not bad, but has some rough points
I was kind of inclined to close the game when I died twice within the first 3 seconds of the game from those instant kill explosions, but I gave it a chance. I'm glad I did, because the game isn't bad. I don't regret playing it, and there's a decent amount of potential here. However, there are some key problems that should be addressed. Firstly, there's a bug where my score and money turned to NaN, so I was able to buy the best upgrade and ship by the second level since there was no limit to my money anymore. That's the big one. Smaller problems include enemies shooting at you from offscreen on the sides. Shouldn't really be allowed to happen. Also, your dark lord with the eyeball should probably speak a little more ominously. "Ooooh, what's this? A resistence?" sounds like something a bratty twelve year old would say, rather than a feared ruler.
Some of the sounds were a little bit annoying, but that's inevitable in a space shooter. Overall, the sound was well chosen and managed.
You should team up with a skilled artist to really bring the cutscenes to life. A scripter shouldn't have a hard time finding one.
An overall scoring of seven may sound harsh, but I don't throw around high scores, so it should be taken as more of a positive than a negative.