HaraForce is cool, but it and others like it lack a certain nuance. There's no mystery. Scoring lacks discovery and strategy. A good shoot em up is challenging, looks nice, and is fun to play. A GREAT shoot em up IMO has a fairly low barrier to entry but a high skill ceiling, rewarding daring plays, patience, strategy, and memorization.
Games like HaraForce and other shmups I've seen over the years on retro consoles for the most part lack what makes a truly GREAT shmup. Blade Buster rewards players for patience - orange ball enemies can be killed immediately, but if you wait for them to open you get bonus points. Big round enemies which enter the screen in 4 parts which come together can be destroyed prior to their joining for huge points. Early on in the game they show you that destroying two large orb enemies at the same time (they turn orange shortly before their deaths) will also grant a huge point bonus. Later on in the game this knowledge comes in handy as two of them come in staggered, and you have to partially damage them into orange (i.e. close to death) but not finish them until they're both on screen which takes a little bit to happen, all while dealing with other enemies, and when they converge on screen for that point bonus it's *chef's kiss*.
Most shmups could be played for high score - do better, kill more enemies, and often just farm popcorn during infinite boss fights, and you'll get a huge score or even max it out. Blade Buster gives you a time limit and challenges you to master your knowledge of the game and that just takes the experience to a whole nother level that others don't seem to be bothering to replicate or work to go beyond. The closest imitators mostly just ask the question "how much shit can I toss at the player at once on the NES?", with some going way overboard and creating a miserable experience. Over Obj is a recent example of this - I found that miserable to play and I love bullet hells. People need to respect the platform and its limitations and work within it.