Not much to improve on...
I enjoyed the game, but thought the game got repetitive after around 10 levels or so. Either way, the game was well presented & loved the changing sprites. My only advice is to add in a simple difficulty option. Perhaps easy giving you more power-ups and reduced speed. Normal how you currently have the game set up, and hard; which reduces the powerups,, blocks move faster (but there are less of them) & laser's don't penetrate through walls. (So if you get the game split into two sides, lasers only effect one side as it doesn't go through the wall).
Good effort, looking forward to #2.