This is a really great game so far, all the animation is smooth, I'd say it's looking good. My only suggestions or criticism would be the fact that you're unable of walking around, I'm sure this is no surprise to you, but it makes it really hard to dodge the artillery from the sides if you haven't shot them yet. Besides that, it's not really obvious how to get coins, I played one run and I wouldn't say I did that bad, but I still didn't get point, it'd be nice if there'd be some in-game elaboration on that.
Further though, it's a great game, the art isn't flawless, but still really good.
Keep it up, I'd like to see what this could evolve to.