Resistance 2 didn't flop. Without a lot of investigation, I'd say it did below expectations, but not flopped.
Fallout 3 shipped 4.7M copies. That's probably over 300M dollars in revenue. That's about as high as most major blockbuster movies do. I'm not sure if any other game, save for Grand Theft Auto, has had an initial shipment of more than that this generation.
http://www.vgchartz.com/games/userreviewdisp.php?id=261
That is VGChartz LONGEST review. And it's NOT Cute Kitten DS