@PangaDayWalker games always show up by default, as long as a supported extension is used. There are options to hide files which is useful in some cases. Asumming you set up your recalbox yourself, someone might have hide games by mistake.
@raultra If you had checked ebbi's profile, you'd have noticed that was his/her only post ever sinced (s)he joined a year ago. And seeing that you're totally out of topic (this is recalbox forum, not a ubuntu support forum), I'm locking this topic.