Infamous is about 15 hours long.

[Vetteman94]

Squall_Leonhart said:

Vetteman94 said:
Does this include doing everything? Finding all of the electric shards and stuff?

I would imagine this will be the average completion time, like they say FF takes about 30-40 hours to complete, where in fact you could easily spend 140 hours + on them (like i did in FFX) doing all the side quests!

I would imagine the main game with all the extras would be at the 20-25 hour mark!

 

Well then that makes this a 40-50 hour game,  which is good amount of time.