This is a really nice idea. I had some trouble figuring out how the controls work and why I'm not able to aim sometimes, but as soon as I figured it out I had fun playing your game.
It is pretty challenging, though. And I found that after repeated deaths (either mine or civilians) I started to use the move mode only to change my angle for the shoot mode and play the game way more carefully. And I think that's not great since this game is more fun in the move mode. So you might try to incentivise that more.
Regarding the presentation, sound is good, nothing bad to say here and I'd say the graphics are even better than just good. They are stylish and well made. I always like it when the edges of a level transfer into the background color.
All in all, fun game, nice idea, looks and sounds good. Perhaps a bit too high difficulty.