bug 1: when changing directions, occasionally the ship will move in what appears to be a random directions before teleporting to another location, I'm working on how to reproduce this.
Update: appears to be when moving in either the x or y direction at maximum velocity, applying a change perpendicular to the direction of travel causes all velocity to be briefly cancelled.
Update 2: appears to still be present in test 8, more details in that post

bug 2: when near a 45 degree rotation, using the brakes will result in an acceleration along the either y-axis to a velocity of -4 and cancel rotational velocity and velocity in other direction (when at y=-4, x=0; when x=-4, y=0).
Update: reproduced independent of any rotation, might be velocity based?
Update 2: appears to be squashed in test 8