Ok this is super easy to explain.
First off if you are playing on 0.5.1 the tapes are gonna be bugged, meaning, you can only earn one of Sammys and anything else you wont be unlocked.
0.5.0 everything works the way it should BUT you will need to make sure you delete your save files from 0.5.1 in order to make sure everything works properly.
So yes that means you have to start all over sadly.
Secondly the "???" is a part of the next big update. Its a shop and you should see it next time the game is updated for us Itch.io users. (SubscribeStars already have the most recent updates)
As far as mini games go, in order to keep it a surprise for everyone else, ill just say all you need to activate is "A stack of cash on your desk"
Ill be checking back here in a few to see if you need any further help. :)