Very early demo so the review may be harsh and prove to be wrong in the future, so consider it more like a warning, but playing this demo I already suspect that the final product will be a generic, bland Japanese game like there are countless on this site, where you grind boring levels for 1 hour then regret not having just watched the gallery instead. Basically it seems to me that the developer has no clue about game design and hopes to be carried by their art, copying things that exist in other games but without understanding their purpose.
The gameplay and art is extremely similar to Night of Revenge, which is a good sign, but your hopes will likely get ruined fast.
Most glaring issue, the gameplay is boring after 30 sec and essentially revolves around spamming the attack button. The enemies are slow and very easy to kill since your weapon stun-locks them, yet they take 3 hits to die, so you need to spend 1 minute mashing one key until the room is cleared, and even though you can literally run past enemies without taking damage (yes, they are that slow) the game still forces you to kill them just to advance.
In a massive game design paradox, you have to take damage to see sex, BUT the enemies are too slow to inflict damage, and even when they manage to, you can escape the animation by pressing the struggle key ONCE (I even did it accidentally), so this is yet another of these games where you have to intentionally lose to see something.
There does not seem to be any advanced mechanics like combo-ing or dodging, the keys are there but you can do everything without them, just spammed the same key repeatedly and got a 30-hit "combo" (do you understand why it's called combo?). Even for a demo, this is very weak. The levels feel empty, there are platforms which serve no gameplay purpose, if you fall you can retry without consequence and this is just annoying. For only 2 enemies there are already ~10 screens and locked rooms which make the game feel like a labyrinth.
The art style looks good at first, but it is not that great in practice, the 2 scenes are very zoomed out and don't show much "flesh" anyway, so you don't really see much sex, the animations also have creampie sound but AGAIN you don't see any of it. Dev, this is a porn game, it is FINE to show the sex in it.
Other minor but concerning issues: the controls are terrible, you need to use the mouse in menu, then it plays with keyboard, and in fact the key are mapped at the opposite sides of the keyboard so it requires two hands to play even though 95% of the time you'll probably only do 3 things move, jump and attack.
The ambience and background are honestly well made but it would have been great to have just one sentence explaining the plot or an introductory picture to set up the mood, idk, so we can feel interested in the heroine.
Night of Revenge is exactly this game but better in every single point. Having low amount of content is acceptable and can be fixed later, but the game design issues are not and need to be fixed now.
I've played demos on this site that had even less content, yet were still able to show engaging gameplay and appealing art.
Lets just chill for now and support the dev, hope he will successfully polish this gem.