Grand Kingdom is good, but I couldn't get into it. i really liked the combat system, though. It's the game I -want- to love, but just can't get hooked on.
Knack wasn't really my thing. I did my part and bought it cheap though.
I really need to make a trip to GS and sell some games. I'm really annoyed that amazon stopped being an easy place to sell my stuff... i get like a quarter of what i used to, which sucks, but isn't quite enough reason to go back to ebay, which i hate using.
I didn't like any aspect of Grand Kingdom.
Regarding selling used games, you know CAG has a buy/sell/trade forum, right? If your worried about getting so little, I'd suggest selling on here. More effort required than Amazon used to (haven't tried in recent years), you'd get much more than GS. If you'd trade at GS for new games, do that here. Just a thought.