An idea could be that giving birth to a monster's child increases yourself in a certain way, but while being pregnant, even early on, you get weaker, that would explain pregnancies being "long" and would make you have to consider when you should try to avoid getting impregnated (if you can), though with no threat of losing, as the dev doesn't want to use game overs, and no reason to actually win fights by force (which is something that should come later on in developement naturally), this idea is kinda pointless as things stand.
Also speaking of game overs, if you can just keep getting beat up and lose over and over again at infinity, there is no need for strategy or even to actually play the game, as things are, without even a level up, you could beat any boss if you just keep trying your luck and hope they miss enough times for you to be able to beat them, I agree that game overs kind of suck, but you'd need a setback to encourage you to actually have to try to engage with the game's systems, maybe not a game over, but temporary setbacks
A basic idea with that premise, if you give birth to too many bearmen (forgot the custom names), at some point, one of them just brings you to his den to breed you a couple times, or you get brought to a goblin village for public use, etc
While I agree that gameplay wise, needing to lose to see content is not an interesting concept, immersion wise, it really does something (at least to me) to make you feel like you need to perform, kind of like Degrees of Lewdity, and depending on how pregnancies affect your strength, it could be more than a temporary setback, if we imagine something like every pregnancy increases one stat and reduces another, and the bear "game over" event is minimum 5 pregnancies before you can escape, that could be a massive shuffle of your build and force you to play differently and whatnot
On the other hand, if that means that once you set your build you should completely avoid pregnancies, that would conflict with the goal of the game, so it shouldn't be too big a threat, maybe have a distinction between getting raped and charming the enemies, just for sake of thought, a point system towards a game over for each race would work on paper, if you have 10 points with a designated race, you get put in the soft game over for that race, if you beat one in a fight, you lose one point, if you seduce one, you gain one, if you lose in a fight against one, you gain 2, and if you get pregnant, you get 3 (numbers are for the sake of argument), and you could have events to influence those too etc, that way you'd be incentivized to avoid fighting sometimes, like if you're fully pregnant and can't fight, your points would rise quickly, and this would become an interesting part of the gameplay if the enemies had better tracking (sometimes it's very cartoony how you have to run after them for a while to get them to rape you) even if only while you're defenseless
I know the game is way too early in development to be making that kind of talk, and the ideas I have presented are probably heavily flawed in a lot of aspects, and the dev probably has better ideas on where to start from here, we will have to just wait and see, the game looks promising, I can't wait to see more
If you must only take one thing from this whole message, please give the option to play as the previous character, even if it's just a reskin (I'm kidding of course, that would be a very low priority change)
