so itch does have a thing for directly embedding browser games elsewhere, which could be straightforwardly used for pico-8 games, but it doesn't seem to work super great with iframely
the pico-8 bbs also has an embed but again it just sort of collapses to nothing
i don't know how iframely works exactly but i'm guessing that if it doesn't recognize something as a Known Embed (like, a youtube video) then it just doesn't even try to preview it? which is not unreasonable but kind of unfortunate here