Yep I understand the game. Like I said, even if the gameplay were smooth, you don't have enough juice and the auto fire mechanic does not suit the game. This is usually the point where I'd try to find something salvageable/positive to say about the game, but I'm really sorry I simply cant, so this might come off as a bit harsh - please take this as genuine constructive feedback:
The upgrades are boring and generic, coins are too plentiful so positioning doesn't actually matter even if that was your intention, the colours are flat, the style is boring, the bullets don't have enough contrast/speed/presence to look impressive (so why even bother having them in the game), and I don't think virtual joysticks work very well on the platform.
I think if you had genuinely exciting upgrades that changed the gameplay, there might be a nugget of something here? But it is buried deep down. I think for your next game you should really focus on finding a core mechanic, making that fun, and then build the rest of the game to support that core mechanic. Currently it feels too much like a haphazard collection of mechanics.