once i saw someone saying shmups are the easiest genre to code when trying to get started with games and i actually straight up don't agree b/c i think their extremely low baseline masks how much effort you get filling in the extremely open container. like they're hard to design
hero core i think is more approachable because it's not a scrolling shmup, it's like half a metroidvania and thus is deeply about the space you're in, the enemies have patterns individually and then the design is entirely spaces and combinations