I like it, found it hard also, got to level 4 before I failed.
I think you should scale the positions of the stars so that they appear more on the right hand side and middle than the left, when I died it was in the first nano second because I couldn’t avoid the very first star.
Perhaps a 3-5 second preview of the level would help instead so I can plan my route through before the trail starts to move.
You could also include a point style system for making the trail go through aliens or rescuing stranded astronaughts.
Another idea would be to make the ‘goal’ in different positions on the right hand side, rather than always the middle, on later levels you could make the goal a moving gap to make things really hard!
I noticed the first time I played it that if the window lost focus, i.e. was covered by the browser window, it didn’t redraw the instructions and I was left looking at a grey box, only after I restarted it did I get to play the game.
Andy.