Loaded, closed to check that music was coming from it, started again, died maybe 5x, got to the bit where half the thing in the right has gone off the top screen. Then when I died I gave up.
aspects (rated +/-)
------: Music starts when loaded. DON'T DO THAT! It's annoying for anyone who loads flash whilst doing something else.
+++: It is a good song
-: it doesn't fit well with the theme of the game you've chosen (spaceships, missiles and whatnot)
----: we die if we go off the top of the screen. It's not mentioned in the instructions.
+: Some of the objects look quite interesting.
++: I like the fact that you have background detail.
-: Although that background thing really looked like it should have been an obstacle
----: the collision detection seems 'fudgy' - i.e. it doesn't always seem like the pixels have collided when we 'die'.
-----: the enemy patterns seem to have to be 'learnt' rather than reacted to. It's more a memory test than anything.
--: no gameoverscreen.
++ this is a demo - might get better.
----: I really don't like the way that moving off the screen can lose the game. So basically we're moving 'forward' at some constant rate, whenever we press up.... it just seems silly.
I actually think you should abstract your game further and divorce it from any real-world aspects, then take a look at it and just focus on making it fun.
It's still possible, but it's heading in the wrong direction.
With better collision detection and enemies you can REACT to rather than just USE MEMORY against (e.g. give them some simple AI, reacting to player position) it might be quite fun.
Keep at it. Stay funky.