Well I've been looking around to find out what exactly constitutes an S+ Rank in ORC for the Great Success achievement, and have found a whole wide range of what people think gets you the rank. Some theories going around:
Must be done by yourself
- Must be above par in each of the four rankings
- All cameras must be found in the level
- Special criteria for certain levels (such as the Spectre challenge in Corruption)
More likely to happen on Professional (this just makes no sense to me)
As I said, these are just theories I found when stumbling around the net looking for an S+ guide, so outside the obvious ones like being above par, I cannot verify the factuality of these claims. If proof is given, I'll add/knock things off this list so we can have a comprehensive guideline to getting S+ ranks.
EDIT1: Based on this guide, we can eliminate "must be done yourself" from the list and "most likely to happen on professional" (turns out achievement was just bugged). However, the special criteria is a little iffy because that same article mentions challenges but doesn't go into examples. I am not quite sure if the author was referring to things like the Spectre challenge, which is the only one I know of, or if he just meant the par for each category in the ranks.