Side-scrolling shooters
I like the art, and maybe there's more to the game after the first level; but the boss is way too hard. He's too hard to line up with while his weak point is exposed, and it's almost impossible to land any significant number of hits to it and still get out of the way in time to avoid the instant-death-beam that starts up again immediately when he closes his mouth. The power-ups are hard to collect in the first place, and then there are none to collect when you die during the boss fight.
If it was a 3-hit boss, it would make sense for it to be that difficult to land a decent attack on him, but with a lengthy HP meter like that, it's harder than most final-final bosses.
Unless that IS the final-final boss and the game just repeats or ends if he's defeated. In that case, the game's too short too.