I'm not sure it's a problem of optimization, the game is quite slow (we should increase speed of meteors) and others parameters have fixed delay (appearance, etc..). I understand that the 64x64 doesn't feel impressive. We try something and I understand everyone doesn't like it. I suggest a little windows and not fullscreen to play it. Or you have to let a distance with your screen to appreciate graphics.
Thanks for your review and your honesty (Hypocrisy will not help us to become better). :)