I'm not sure if there is one already as I couldn't find it, but a way to teleport back to the castle (or to any unlocked checkpoints, preferably) would be great. The game is not linear, so you have to backtrack all the way back to a crossroads to access another side of the map. The backtracking is not very fun. Also the merchant is only in the castle at the start, so gathering any essence is basically meaningness unless you backtrack ALL THE WAY back to the start.
Apart from that, everything's fun. Enemy types could use more variety than "this one does melee" and "this one shoots projectiles" - the Sadako enemy type is great, but there's very few of it, the Naga is good but again, very few of it, the Medusa is good but again, very few of it. Would like to see more enemies with fun mechanics rather than just "this one hits you and this one shoots you" that is basically everywhere else.
The high-tech area could use some more enemy types than just floating balls that create infinite chainsaws and the occasional flying shemale demon. I'd even suggest the two don't thematically fit together - the flying demon probably fits better in the fleshy part that follows.
A better-explained "lust" mechanic would be useful - it doesn't seem like there is a "lust" bar, but there is an item to increase lust by 50, there are effects that increase your lust gain over time, but what exactly "lust" is, how much of it there is, and what it does, are very unclear.
TLDR: A fun game, but could use some quality of life improvements like teleporting between areas and some clearer stat descriptions.
