I like the game’s concept!
However the design of the stage tends to favor the top immediately, making the rest of the stage moot. It also favors quick play, in which the missiles don’t give much chance to.
With a bit of tweaking, this can work very well! Well done. Oh, and at least a button for restart and/or beginning the game. The game starting immediately actually gives the one playing it panic and confusion, no breathing room, rather.