Sanzaru is a San Francisco Bay Area developer that noticed one its favorite franchises wasn't getting a fourth installment and thought that sucked. So the studio got the PlayStation 3 development kit and sat down to create a Sly Cooper demo, from scratch. With no assets from Sucker Punch -- the developer that created the franchise but had since moved on to Infamous -- Sanzaru went to work on their version of the "Thievius Racconus."
In a month, Sanzaru created a playable demo of what it though Sly in HD should be. Sony agreed with the vision and -- perhaps more importantly -- so did Sucker Punch. That led to Sanzaru porting the original PS2 games to the PS3's Sly Collection while working on what would go on to become
Sly Cooper: Thieves in Time. They're not reusing code from the games they ported but instead are learning techniques from it.
Excerpts from:
IGN