6th in the global list, is this the best launch for an H game till date?
I'm sorry but that's not even remotely true lol.
1. It is only on new and trending games with less than 800 players (for comparison a recently released f2p mod of a 2005 game has more people playing/reviewing it)
2. It has never been on the global top seller's list nor will it ever be (not because the game is bad but simply because it won't reach the required purchases)
If you are seeing it in your own steam top seller list then please keep in mind that the list is created based on your personal interests and overall regional purchases, which obviously differ region by region.
AFAIK, Being a DIK is the most popular and most bought H game on steam.