Not really, those games are very simple code wise. A high schooler could do it (source me).
You could make a bullet hell game engine as a project in an intro CS course.
The hard part is the content in the game, and ZUN was already a composer. That just leaves the code which is easy, and the bullet patterns, which ZUN clearly improved at through his earlier games. (and the art, which is famously bad though endearing)
The other comment said that obviously no solo dev do everything by himself. They must have asset maker or song maker who do all things mostly uncredited. But, here we are, of course there are true solo devs!
> Not really, those games are very simple code wise. A high schooler could do it (source me).
That very much depends on how much they did themselves. If they used unity, and went very light on the simulation, sure.
> You could make a bullet hell game engine as a project in an intro CS course.
No you couldn’t. Well you could but it wouldn’t be appropriate for actual beginners unless you stripped it down so much that calling it an engine was meaningless.
> No you couldn’t. Well you could but it wouldn’t be appropriate for actual beginners unless you stripped it down so much that calling it an engine was meaningless.
You definitely can. One of the assignments in the CS intro course I took was a bullet hell game. "calling it an engine was meaningless" is an opinion that requires ignoring the fundamentals of what a game engine is.
A game engine is a framework that allows you to create games. Assuming you don’t have tons of content (and I’m sure you didn’t in an intro CS class), building a game is an easier task than building a game engine.
Let me ask you this. What were the parameters of your assignment? What libraries were you allowed to use.
By modern standards, yes, writing a bullet hell shooter game is not hard.
But ZUN started on the PC-98.
To put that platform in a western context, imagine if IBM had gone with planar graphics for VGA. Or an Amiga with no coprocessors, sprites, or scrolling[0]. You have a lot of pixels to fill and no help to do it with. It can't even run DooM[1]. Most other developers threw their hands up and shipped RPGs, erotic visual novels, or porn. Getting a fast action game running on PC-98 is a genuine accomplishment.
[0] I am aware that I just described a compact Macintosh.
[1] https://www.youtube.com/watch?v=Fj0-KvV0SC0
What you described is even better: an Atari ST :)