This game looks like it's a great start with a ton of potential. The dev's Patreon page shows a lot of progress making good on that potential and I think this game could be a big time classic when finished.
However something about the animations seems off. I can't land on exactly what it is. I think part of it is the H animations start so slowly and passively. It's almost like the girl is just standing there on the dude stuck to him. Feels like there's a lack of motion, or maybe even aggression, that would make these animations better and more, well, involved.
Also if the animations are going to remain defeat and damage-triggered, I think some unique game over scenes would add so much to that formula that they are impossible to leave out. They bring a lot of fun and tension to the game to avoid a game over and the sick stuff that comes with it. I like the idea of the alien-zombo dudes carrying the girl off to some dark part of the ship to do some real dark, special stuff to her, but it's just a standard animation in the current version.
Also, making each animation only trigger under very specific circumstances can make them a huge pain to unlock and remove a lot of the fun, tension, and satisfaction of playing the game. It can quickly become an annoying "catch em all" game as you purposely lose over and over in a certain way to fish out the missing animations. The demo currently has a lot of this.
Overall this looks like it could be seriously memorable. I like the advantages that 3D brings over hand-drawn, but I think that the disadvantage of 3D is that animations with 3D models seem to have a higher chance of looking very wooden and sterile since you are working with meshes and bone nodes that can only be posed in certain ways. Reserving my judgment on this one but it's definitely my most closely watched game atm, great demo release.