Try this:
$reviews = $page->children()->visible()->filter(function($p) {
return $p->scores()->toStructure()->filterBy('platform', '==', urldecode(param('platform')))->count() > 0;
})->sortBy('posted_on', 'desc')->paginate(11);
Try this:
$reviews = $page->children()->visible()->filter(function($p) {
return $p->scores()->toStructure()->filterBy('platform', '==', urldecode(param('platform')))->count() > 0;
})->sortBy('posted_on', 'desc')->paginate(11);