Fun game but repetition is its name
The game has a fun feel and atmosphere to it, but is dragged down by both repetitive music, sounds and gameplay - the same sounds play when you get hit, shoot at monsters, or ram into something and there are only three music tracks I can think of - the normal level music, the boss fight music and the boss victory music. Each world may have different colours than the last but the backgrounds never come any closer to you and running sideways doesn't achieve much to change the horizon you can see. The gameplay does not change very much and so becomes repetitive after a while, especially boss fights as the bosses are the same - the difficulty is only upped by adding in more space worms (or whatever they are)
I cant quite put my finger on this one though, because despite the dragging repetition, it is still quite a fun game.
This is worth a decent try at the very least.