Reference added: 459 "Super Darius and Super Darius II."
Bigger and badder than the prequel (see entry 459), but shooting large robotic fish is still the order of the day. The music and graphics are some of the best that I've encountered on the system, although the sound effects (without the music) are rather poor.
The game is quite stingy with powerups, although one of them is a shield that will block something like four or five shots for you--a nice one to find. Mostly though you're just plinking away at swarms of enemies with normal bombs and single bullets, and I have to confess that I switched auto-fire on after a while to preserve my thumbs. The enemies tend to be pretty good-sized sprites, just like your ship, so it can be challenging to avoid smashing in to things with even just a single enemy swarm on-screen--and starting in the second level you get more than one at a time most of the time. Whew!
I like the old scoring mechanism where you get a bonus for shooting down a complete group of enemy ships (fish? :P), and the giant fishy bosses and midbosses are pretty neat. As in other Darius games (Darius Gaiden for instance, entry 62), the path branches after each world (the worlds are literally planets in our solar system, neat!), so you get a good deal of unique replay value just out of that. All in all a very impressive game.