This is a very good concept, and I do enjoy playing it, but it is a 4/5. You could update some of the graphics, and I do think that all of the modes are fine, there are many of them, so it should keep people entertained for a long time. What I think you should add is to try to make the things look better graphics wise; to draw the player into the game. The gameplay works fine, and it all works well. I want to know, will you put in the Kongregate API? If so then it would make the game much more fun to compete with. All right, this is a good game, just some graphics and it will be a 5/5. :D
Also, there is a couple of bugs like when I started level 3 a huge asteroid just popped right into me, and then I lost a life. Another thing is that when I had tried to go through somewhere, the meteors hit me, even though I wasn't close to it. Happened on a couple of occasions. Really good game. Can't stop playing it... :D
Personally, this is a 5/5 for me. I have never actually enjoyed playing these types of old school shooting games either, but it seems as though this is really good. The style captured me into the game; definetly I will add this to my favorites, and play some more. Also, it seems as though this is too much of an old style game. Maybe if you one-upped some sort of powerup, or when you change levels a pause screen happens you could add some sort of leveling up material based on the things you destroyed, etc... each one would get special points, stuff like that. Also, many people have said maybe making it smaller, it's good for how fast the thing goes. Also, for me, the controls were awkward, but after a while I got it. Another thing that you could add in would be another thing to toggle quality, I have a kind of slow system, if I could play in Medium Quality, that would be good. I still liked it very much, 5/5 and +fav.
Very nice concept, some bugs, and the difficulty is good. If you could edit this some more, and then try to work more with things that could help out the player to make it easier on him/her, that would be great. Whisper if you want some more info. Also, great work. :P