How long? I've rushed through to #12 and it seems still simple. (You do always the same things up until now). But how many "challenges" are there? I don't wan

How long? I've rushed through to #12 and it seems still simple. (You do always the same things up until now). But how many "challenges" are there? I don't want to spent the whole day decoding files even it seems kind of funny. Besides that, really great tool! Didn't know about it until now.