Pretty much what it says in the subject. I have downloaded 10 different sub-games, which plus minetest_game and minimal make it so that one game is not displayed... I can make worlds of that game, but not play them through the singleplayer menu... There are workarounds, but it would be greatly beneficial to have more space if people are being encouraged to make sub-games.
I'm not sure if this should be here or in feature requests...