Very nice
rendition of the old russian classic Tetris. At first, my thinking was to suggest you jack up the difficulty faster but then I realized I probably wouldn';t have played up to level 10 and for as long a time if it had been harder. The sound effects are very satisfying - great job with them.
You might want to play with the idea of having the plane unload a brick or two now and then -- when I saw it, thats how I thought it would be.
Also, regfarding the gridlines -- some people I'm surte will suggest you remove them but I say keep them in.
Great job1