Really enjoyed this! So frustrating! But satisfying and consistent. It took many plays to develop better strategy. As best I can tell, you have to focus on putting perpendicular walls between you and the enemies. The only times they slow down are to change direction and if the rub up against a wall. And still I couldn't get more than 500 points. Kept going in for "one more try". Let me know if you decide to implement multiple levels or more power-ups. Great job!