Much better!
This is by far a great improvement from your last one! I won't go into much detail because a lot of the stuff that I stated in my last review could also cover everything in this review.
Animation/Graphics - The circles and the square looked a lot better in this one than they did in the last one. The color was much better and the animation itself was much cleaner.
Story/Content - I really liked that you had to collect something in this one. I also liked that you had levels. Good job on making it more fun like this. I liked the fact that you had checkpoints. I recommend making the game a little longer though because it barely took me anytime to beat.
The only thing that I can see that is wrong is when you take your mouse of the screen on (for example lets use this side) the left side you can then move your mouse around the screen quickly to the right side and you will instantly appear on that side out of harms way of the green circles. If you want this there than I say keep it because it's a nice strategy if your stuck, but if you don't want that there than I would recommend making it so when they do that the square travels across the screen to get to the other side.
Audio - The music is ok, but if you lose the level and try again the music stops. I recommend fixing this so people can listen to the music during the entire game instead of it stopping.
Overall - You improved a lot from the last one, but there seems to be a lot of things to still work out. Good luck and keep working.