Yes, you can use downloads and there are all kinds of cartridges you can get, I have listed two games on my auctions. You can learn more on the vtech website, or Google Innotab 2, there's probably a lot I don't even know about!!
I can't do GIN yet because I'm still a little new and haven't earned my sellers wings badge yet. And you'd have to be bidding against someone to raise the points