Like I said, it really depends on how many cards because if you put too many the snap mechanism will close, but it'll be a bit open up and so it won't "close" like it's supposed to. Instead of the wallet closing tightly like a nice sandwich, it'll instead bulge a bit on the side where you put the credit cards, and it'll look like it's about to "pop" if you get what I mean.
From my experience, I was only able to hold 1 card in the specific credit card holder, then my ID and my Best Buy Rewards zone card (I shop there often), and another miscellaneous card or two, and a few important receipts, and that was enough for it to start to feel slightly bulky.
I'll post some pictures tomorrow when I get out of work to explain what I'm talking about.