I had a some difficulty using the break. I click several time to slow down efficiently and eventually get to a full stop, after which the break either don't do anything, either throw me at full speed on a wall!
Bullets seemed also a bit too fast, and hard to read.
Nevertheless, the concept is well thought. The mechanics are simple enough to be understood, yet offer a rich dynamic. With a bit of tweaking, it could give a great fast-paced shooter. Nice job!