Schmups fail at captivating the heart of gamers because the act of attacking feels like a boring formality. You hold down the attack button and that's it. You unleash a shower of pew pew that the enemy doesn't react to and you just forget entirely about it from now on, because all you have to do is dodge the boss until their life bar is depleted. Why attack at all? It doesn't spark any joy. In a game genre that is known for visual clutter, why introduce even more visual clutter through attacking? As cringe as it may sounds, Undertale improved the schmups formula. Just make the player and the opponent take turns. You dodge bullets when on the defense and when it's your turn to attack you do a basic minigame for attacking the enemy. There is no reason at all for engaging with schmups gameplay when such a simple variation is 10000% more interesting, albeit only Undertale does it and people don't even praise in particular for its combat. It just shows how close schmups come to being enjoyable but miss the crucial part of being fun.