Thanks all for the kind feedback and nice words :) I'll have a think about the controls, I tried many different control types and found this method the easiest to control from a computer keyboard (and future portability to touch devices), You can kind of stop by holding down one direction which puts you into a spin and holds you in place, also you can rest against the walls.
I want to make a game that people enjoy playing so if the lack of being able to slow down is detracting from that enjoyment then the game isn't as good as it could be so over the weekend I'll have a play and see if I can come up with any improvements without compromising the simplicity of the gameplay and controls.
Again thanks for your feedback it's really appreciated.