Thanks for playing my game and put some effort to get it worked... Of course you should be able to shoot on this demo level, so I have immediately checked the code and it seems it is my failure, the mac was not included in case of shooting and initial windows resize. I am sorry for that. The next update will include the fixation of the bug.
Also thanks for the other observation, we alreday revised the starting of the game, but based on your feedback I will still consisder further revision especially for initial phase.