Your idea was great! I did not like the controls though, the sensibility was too high for me and it may have been an issue with the programming, if you put the function that moves the ship on Update() then the faster the player's hardware more often will the ship move, making it faster than intended. I also prefer to use the arrow key rather than wasd when there is no use of the mouse.
The game was pretty easy, even with 9 ships attacking the asteroids, you could still outheal their damage, also following the principle of "given the chance the player will optimize the fun out of the game", the best strategy to win would be to leave a single ship alive and use it to charge everything which is not as fun as joggling the tasks.
All in all a great game good luck in the competition!