OH MY GOD IT'S A GIANT SPACE LIZARD! :D
I didn't experience your game as sluggish actually. You could try lowering the cooldown (but then also the damage?) of the main cannon to make it feel more responsive. What I miss mostly is a challenge that's more than a timer. If for example instead you would get 1 point every second (so still the timer element), but also 1 point for each asteroid you kill, and double (or triple!) the points if you do a trick shot kill. Then I would have something to make me want to keep going more. Still I liked it - cool that we both had the damage = change AND shooting = moving + deflecting combo :)