last update after the challenge

Thank you all of you for the nice challenge!

I've read the comments, and I've done several tests to see how I can improve the game.
The main concern was about the random aspect of the game. I've tried with more predictable patterns, but I don't really like it.
In fact, I'm not sure I agree with the fact that this game is more oriented "random shooter" than "skill". Of course, if you fire just one bullet, then the fact that you will hit or miss will be random. But the point is that you can fire several bullets correctly placed such that you have 100% chance of destroying the target.
So, the required skill is deeper than just "clicking once a the correct place", it is "clicking several time at the correct places". It introduces aspects that I think are more interesting. For example, you can choose your target or move to a specific position before shooting knowing that some bullets will miss.

I have uploaded the updated version, just for consistency.