My honest opinion as a fan of your games:
The story is looking good, although it isn't that much complex: The system is corrupt, go join the rebels and do stuff (and we don't understand much of what we're doing there yet) , which I take is on purpose so it's okay. And I like the system of one smut scene per "chapter" (I don't remember if that's how they are described, but I mean the story between the game stages).
The art is amazing as always, whenever a new background shows up I hide the UI for a bit to take in all the small details and characters it has scattered around. I'd even suggest having a simpler UI only for the first or couple of first frames when there's a new background art, because the current one hides a good chunk of it. I think it's fair enough if you're applying so much effort in those backgrounds.
Now, the tower defense gameplay is a bit monotonous. It looks a lot like what you've done with Robin Morningwood's minigames, you took a game concept (plants vs. zombies) and made it fit a desired theme (in this case, sci-fi bara sex), except in Robin Morningwood they were just minigames and there was a lot of variety between them, while in Surving Purge it's one of, if not the key point of the game and I don't see anything too special about it compared to other tower defences (except the sex and NSFW theme).
I hope that this demo was just the tip of the iceberg gameplay-wise and we have more excitiment in the future. I believe that with new locations in the Purge to be unlocked we will have new enemies with new animations, that's something I guess.
I don't have much to say about the secret base, it looks good visually and the concept is attractive but it looks like something I'd find in a mobile game or something, since it's mostly an AFK game. I was excited about having characters "interact" there (if you know what I mean 👀), but it's just the same animations as the tower defense game after building enough libido... It looks to me like this mode is a bit under constructions so I'm looking forward to see what it can become.
Overall it's a game with some itty bitty drawbacks but that I'm excited to see what it will present in the future!