WOW! This game GLOWS! GLOWS everywhere and it is so cool to look at! The dying explosions when we kill an enemy is eyecandy too! One suggestion I have is: make us jump using the 'spacebar' and the 'up arrow', because some people prefer using those to jump and it's not hard to implement it.
This game has room to grow (like different enemies, guns, level layouts) and you know it! Good job.