Resistance 2 for PlayStation 3 Takes 420 Hours to Complete
And by complete, we mean complete complete. Sony says, and you may already have heard this figure tossed around, that there's some 420 hours worth of play time in Resistance 2 required to unlock everything.
Thankfully, for at least my own review purposes, the single player campaign should take you about 9 to 11 hours to burn through. That's totally reasonable.
But if you plan on dedicating the time to do everything, unlock every level, find every briefing, max out every class, you've got about 18 days of your life ahead of you just playing R2.