Mark Cerny , who was a programmer for Sonic the Hedgehog 2 for Sega , convinced Naughty Dog to focus its new resources on creating a character-based platform game that would fully exploit the 3D capabilities of the new systems .
Mark Cerny , who had produced Sonic the Hedgehog 2 for Sega , convinced Naughty Dog to focus its new resources on creating a character-based platform game that would be in 3D .