Hello, Nobume
Thank you for your interest.
I do plan to release all my games on Steam eventually, but since there are additional cost to putting games on Steam, I tend to only do so with those games that are popular enough to cover the cost of the application etc.
Sadly, 'Devil' hasn't managed to cover its own costs yet, so I can't conscience spending more on releasing it on other sites right now, but I have hopes my upcoming games will be popular enough to warrant it.
Thanks for playing