First off, I think the 3D Tron-like style is really cool. Good job on that
I liked the concept but as others have said, there isn't anything keeping me from just running in circles at the far edge. I got to level 33 only taking damage 3 times before I quit. What ends up happening is there isn't any interesting choices for me to make, besides occasionally switching directions.
I think there needs to be incentives to go towards the center and bob and weave enemies. My first thought is that maybe the energy beam is always draining power and you need to go after batteries?