Gifting seems broken for me - "gift back" button leads to a pupup that keeps telling me I have no friends. And when I click "add more friends" the popup just closes without any further dialog. Annoying. I'd really like giving something back when receiving a gift!
The hard badge is very easy actually... when the first big meteor comes, juggle it in the screen, don't let it fall out of the screen. Hold it for 10 minutes (easy!), you got the badge :-)
 "Backyard Monsters (removed)"){kind=icon}
 "Bloons Tower Defense 4"){kind=icon}
 "Red"){kind=icon}
 "Starfighter: Disputed Galaxy"){kind=icon}