I'm almost done with it. Just have to defeat the last Shai Gen mob boss. I've currently collected just over 300 agility orbs and over 60 secret orbs. Still need to get my driving and shooting to 4 stars.
One problem with Crackdown is that once it's finished, there isn't much to do - except do races and collect orbs.
I want to get my driving skill to 4-stars, but can't as there are no gang members to kill. How does one get gang members to respawn ? Somehow I don't think you can.
You can get all the gang members back. I forget what the setting is, but it's on the same screen where you can choose the look of your agent before you start the game. Yeah replayability of Crackdown is <<<
I still have the blue orbs to find but if you wish to level further up after you have done the bosses you can go and do the TIME TRIALS from the game menu. You may even pursue this with a buddy in COOP for the achievement.