Really cool concept! I guess you're still firing but I liked it a lot. It takes a few seconds to get used to tapping in rhythm while controlling the ship with the other hand but I ended up moving on the rhythm more often than I would like to admit. Playing this with a controller would probably resolve this problem, but take away part of what makes it difficult.
That's a main drawback of this hybrid game mechanics. You have to however condition your both hands in good control of the ship, like drawing a circle with your left hand but drawing a square with your right hand simultaneously. In compensation of this drawback I tried not introduce anti-rhythm patterns of bullets and for all purposes I'm glad to see this worked.