First, I should mention that this was an awesome month. There are multiple releases worthy of consideration for the winner and there are two releases that will be added to overall consideration for VN of the Year 2017.
The actual twin candidates were: Yami to Hikari no Sanctuary and Imoten
The runner-up was: Junjou Karen Freaks
For various reasons, I avoided playing several VNs this month, including Boukyaku Shitsuji and Tsugihagi Make Peace. The biggest one with the former is that it is yet another VN in the same setting as the 'Uso series' by Campus. With the latter... it is that it is a relatively high-end charage appearing charage by a new company. To be honest, Tsugihagi is not something I want to play right now. It will probably take me until the end of the month to be human again after trying out Giga's massacre of that game. If I played it now, I'd take my anger out on it, and that would be... unfair.
Imoten and Yami to Hikari no Sanctuary are both great games... falling somewhat short of kamige level, but then, there haven't been any kamige releases this year anyway so far. I actually struggled a lot when considering the two. Either one could be VN of the Month for October... and in the end, I couldn't decide. As such, I announce the rarest of the rare... a tie for VN of the Month October 2017 between Yami to Hikari no Sanctuary and Kanojo wa Imouto de Tenshi de!