Very neat and there are lots of good things about it but there are some rough parts too.
The good:
Probably among my favourites as well in visuals and audio. Very well done as they give it a lot of cartoonish charm and its very clear what's happening with each sound effect. The music is also a great choice in delivering this light-hearted theme the game has going for it.
The camera work is very great but can be difficult to spot bullets when the UI blocks the bottom of the screen where bullets can come from.
To improve:
Gameplay is simple but relatively not challenging. I can see why you were worried about the challenge.
I think you needed more playtesting to help gauge the difficulty and create a more engaging game overall. While I was very much pulled into the very vibrant world and colourful graphics and great sound, I was also relatively disengaged after the simple gameplay.
I think you needed a faster rate of customer orders to keep things going at a faster pace.
Neat!