Developed exclusively on the same platform as the target platform.

Note, this doesn't mean developing for different CPUs. A game compiled for 680x0 Mac on a PowerPC Mac should not be included. Neither should a FAT binary game. And before someone mentions systems with multiple architectures (an Amiga x86/PPC dev system for example); if the final game it meant to run on a system without multiple architectures then it doesn't belong in this group. The only way a multiple architecture game should be included is if the game only runs on the same multiple architecture platform.