Thanks acidDICA - that truly is an amazing oversight and I'm suitably embarrassed! I guess I've just been on automatic testing the shop which has been in place for some time. It's fixed now and I'll consider making the coins momentarily invincible. That's exactly the reason why the "1" ball takes two shots to kill. Originally "1"s would be destroyed on the first shot - imagine how annoying that was!
Thanks again for everybody's comments. I've uploaded a new version that fixes the issue with the keyboard. I'm having trouble with both the chat and the high scores myself but having implemented Kongregate's code I appear to have no more control over it :-/
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