(Considering the linked section) that is more or less how Petra Engine[0] came to be - making a gamejam game[1] for MSDOS over a few weeks. Though while i did make it for that specific game, i always had in mind that i may want to use it for other games in the future too so i tried to make it more "generic" and keep the engine and game bits separate while avoiding too many game-specific stuff (didn't fully manage it though - in the end i've been removing PAP-specific things and a bunch of hardcoded stuff over the years whenever i feel like using it).

That said, despite making a bunch of demos[2][3][4][5] since 2021 when i made the game, i never made any game using it after that as i always lose interest - perhaps i do need to be making an engine from scratch to keep myself interested :-P.

[0] http://runtimeterror.com/tech/petra/ (note the version is very old and i've made a lot of improvements since then - this includes the Codeberg repository which i'll move somewhere else at some point)

[1] https://bad-sector.itch.io/post-apocalyptic-petra

[2] http://runtimeterror.com/pages/iv/images/44d7537fb719e00fdcd...

[3] http://runtimeterror.com/pages/iv/images/d22ff83dd5e5109e02e...

[4] http://runtimeterror.com/pages/iv/images/1da6a4bce430a8d8507...

[5] https://www.youtube.com/watch?v=zx9KmkTLcB0

> perhaps i do need to be making an engine from scratch to keep myself interested

you're not the only one. jonathan blow has made tons of money selling games and also needs to write a whole programming language for 100h to keep him interested enough to yield 1h of content.

i can't really say much about the people who say don't program game engines (or whatever thing they don't like) in terms of opportunity costs (a generous name for this category of complaining), other than they would be bad at both making art and making money.