His two podcasts with Boghog and Aktane are basically that and they are both great, especially the one about TLBs

I really like dynamic rank systems in shmups as a way of dealing with the need for varied difficulty. You don't need to guess what the game means by a difficulty level before playing it, and it's much more reactive and granular.
Granted it's difficult to make that work in a context of a platformer

youtu.be/oKED6xhcq8A

I use GameMaker, which has it's own coding language. It's pretty easy to get into and flexible enough so I don't feel restricted while developing things, so I'm quite happy working with it overall

Thank you for your work! YKK really deserves it

Oh, yeah, that sounds like a very good method to keep you from sticking to the same path every time but still leave you with a choice. I really should get around to playing GnGR

I feel like this also works especially well with routes, because then you have RNG variation on top of variation based on concrete choices of how you go through the game, so then your runs can get very different from one another.

Something like that is quite difficult to do because it's scary to not be able to predict how your own game will play out, even though it's very worthwhile if you nail down the execution of RNG elements.

It's a really good genre! I would recommend ZeroRanger and Blue Revolver for going further into it.
Oh, and also Radiant Silvergun, it's made by the same studio as Ikaruga.

Thanks for trying it out! The disappearing is mostly to avoid the hud elements obstructing your view, might make the hitbox for that stretch more horizontally to make it more consistent.

The demo is on both steam:
store.steampowered.com/app/3169340/...
and itch:
kornodd.itch.io/rainchaser