Could you give an example of those other game jam pages?
Viewing post in Make game jam pages look good
Something like this: Bullet Hell Jam 2023 - itch.io
Is this one just exceptionally good, or am I missing something in my creation?
Ah, yes. Looks like that one has custom CSS enabled. You must contact support to get that. However, there’s a reason why it isn’t allowed by default. It is possible to make very good pages without, and CSS can be abused.
I don’t know what your jam looks like, but I have a feeling it’s more to do with that than any lack of CSS.