The fact that the wave height and angle are given to you, and all you can do is decide when to fire — that's what makes this game such a unique experience. I think the joy of landing a hit is so satisfying precisely because it's not intuitive. If you develop this further into a single-player mode, it'd be even more fun with features like showing the trajectory before firing, or letting players upgrade the cannon's performance or unlock different types. I haven't tried PVP so I can't speak to that, but even if you took it in an agar.io kind of direction, I think it'd be really exciting!!