Half of that $5000 is from a single pledge. Is it possible that they pledged $2500 to themselves to make it look like their project is getting more attention than it actually is? Or does someone out there just really really want this game?
Mostly likely that's exactly what it is. I know if I were to run a scam like this, the first thing I'd do is a bunch of fake pledges to drive eyeballs. I think the total overhead is about 10% (split between Amazon and Kickstarter), and of course you only end up paying it if the scam is a success.
You wouldn't actually need to pay the money. You'd just need to make sure it got pre-authorized. Then once you got another legitimate pledges you could withdraw your fake ones (or leave them up but without any money in the accounts, I believe it's fairly common for KS not to be able to collect al the pledges at the end)
Known as "salting" (found out in Cialdini's Influence)