The following updates have been implemented:
Just a small update this time, but may be a very important update for someone :)
Added +3 lives on the Thumbsucker difficulty.
Now you have 6 lives on the start (3 hearts), but if enemy hits you each hit takes only half heart.
Added option to fire with Left and Right bumper on XBox 360 Controller.
Thanks to Titomosquito187 for the great support and ideas. :)
Enjoy the game!
ps. I'm working on a new game :) Stay tuned!