Fascinating
That was a real fun game to play. I've always enjoyed getting bonuses. You took a simple concept and made it interesting. Snake, tetris, and the rest of the animation changes were pretty cool. However near the end of the game, I found myself bored. Like the game could have been improved a little.
Going through a tunnel can be very hard. A random mine got in the way of my path and I couldn't do anything. Next I found myself supersized and trying to going through. The problem I faced was the game began to be exhausively long. I think I was going to break my cursor. Perhaps make it so you could use arrow keys. Could you add a bonus ability? Get an absorb ability and use it later in the game where all gems come flying at you, perhaps? The boss fights were interesting, but the looping music got annoying when such a fight is drawn out that long. After dying on the third boss, I realized that I may never get to see the last boss. I think you should be able to save your progress between each boss.
There were a lot of things that I didn't like, but I can't complain much when you developed such a creative game.