The physics based aspect works pretty well. It does remind me of Angry Bird.
I like that there are different ammo you can collect and then use in new levels. But I find that the levels are really easy and straightforward, there's really no need to use anything other than the default one, so it defeats the purpose of the different ammo type.
The UI can be pretty buggy. I can drag the dragon tail to the bullet respawn button and then both won't work. Luckily I guess I can use the reset level button to reset everything but it's not ideal.
The visuals is not bad, but I'm not sure why you chose to zoom all the way in with the background and make it looks really pixelated.
Music is fun but I would have loved to see more sound effects.