Well , per say I am content with the game .Although I could suggest that in the future:
-as a winning scene it should be introduce that the player comes back to its normal size and engages in a victory rape with the succubus , to which it could be added some position switches and a creampie scene as a finish(it could be a button pressing sex batle too)
-a larger variety in cloths for the succubus customization, including a naked option , maybe a slightly buff-ed version too
-different attacks like a boob-squash one ,like the one he picks up the player , only to not eat him but to squash him between her boobs ( it could be condition depending on how many times she got knocked out by cannons or to how close her health bar goes down, which it would be appreciated if a health bar would be implemented) as well as inserting the schrinkend player into her pussy resulting a game over
-crossbow should have a liniar marker when aiming , like the one with the cannons , its kinda frustrating to continuously shoot the arrows only missing by a little bit off target (also maybe more arrow slots , like a quiver maybe? ), arrows could be used to shoot her to drag her attention too , in case the AI is going dumb and not really reacting to the player.
So far that's what I could think of for suggestions in enhancing the experience of the game .I hope it will go well