I really loved the game... after I switched to wsad :)
This is a plus btw- having different options, so that players can play the game in the way they enjoy!
Other than that- this is what this jam is about. You used the theme the way it should be- the limitation is obvious, and it affects the gameplay. Also- it changes, and you can make the space less limited, if you are willing to risk it, and try to stay in the circle! Really cool.
Other than that- all elements of the game are really well made. The music track fits the game perfectly, the graphics are instantly readable, which is what they should be in a fast paced game like that! The controls are precise, the patterns challenging, but not unfair.
Only thing is- I can't tell if the game has an ending, or is it an endless game. My best time is 3.14 so far!
Over all- that's a grat game! Keep it up!