You can usualy submit your run even that would be slower than run on human difficulty. We didn't add difficulty sub-categories for IL's because we didnt expect that's someone would run IL's and with current interface will be difficult to navigate on IL board than on fullrun board.

with the IL leaderboard adding the diffuculties could be done but it would make the board massive. i only see an option for it if there was a bigger demand otherwise IL's are seen as a speed challenge and not a difficulty challenge