[ EDIT - This review reflects opinions on version 0.0.35 ]
I really like the idea of this game, strong ambience. There are a few issues that I can see with it so far, not sure what the devs continued intentions are for additions to the game, but I figured it might be helpful to list some of the issues I see.
Gameplay Mechanic Issues
No Driving Factor - Other than upgrades there is no real reason to go out and grab materials. The problem of course is that means I'm gathering materials... so that I can better grab materials. I think a decent solution would be for the goblin things she's interacting with to be constantly charging her rent or for transportation. If she doesn't have the cash, she can pay in...*ahem* other ways. The goblin sex scenes could be repurposed to this end.
Things are also worth WAAAAAY too much money. She should struggle to get rent and pay for services (because of course the goblin things will overcharge her because they want to fuck her), so you should be incentivized to take greater risks to fill your packs with more worthwhile items per trip.
If she fails enough times and morale gets low enough (see below) or something, it's game over and the girl just falls into being a goblin fucktoy or monster fucktoy.
Additionally, different more secure lodging could cost more money. Otherwise, sometimes after sleeping for a day she gets raped.
No Failure Penalty - Sure, the monsters can be kinda gross. But I'm here to see the sex scenes. There is no gameplay incentive to not just go out and get caught. The girl has no morale or corruption to keep track of. Morale or corruption could possibly make it harder to collect things, or reduce speed. The point is it should provide some kind of overall detriment to moreso align the player's goals with the girl's goals, since I assume she doesn't want it to happen.
No Failure Penalty Pt2. - I LOVE the whole dragging her away little cutscene. That would be wonderful to expand upon, where instead of being transported back to the hub, she instead wakes up in the nest without equipment and has to escape. After a certain amount of failures to escape the goblin things could rescue her... for a price.
Underwhelming Scenes - The monster scenes only involving foreplay acts seems like wasted potential. Additionally, please introduce the climax aspect at the end of the scene. Not including a climax for either party leaves the scene feeling incomplete. Additionally, the girl's face could use with more expression. She looks like she's uncomfortable because someone cut in front of her in a line, not she's being sexually accosted.
Torches and Sound - I like that different monsters are attracted to different things. However, in the first area it's literally a detriment to turn any torch on at all. Plus, it's bright enough that I can already see. It's too easy to get around the monster's detection capabilities. Also, the timer on the torch does not feel good if I'm already disincentivized to use it for other reasons. Either infinite charge with penalties for using it, such as attracting attention, or at least let it recharge and have some visual indicator of how much torch I currently have.
Gathering is too Painless - Gathering should take time, and attract monsters. Potentially being interruptible. It's really easy to just sprint about the area spamming the grab key and then yeet out with no penalties or real interaction with the environment. Locking your camera to effectively blind you for a few seconds could also heighten the tension of doing so.
Suggestions
First Person Lock - I actually rather like the whole locked to first person thing, it's really unique. That being said, being able to see what's going on would also be nice. I know we can switch it to third person, but it sort of loses some of the ambience the locked perspective grants. So my proposal would be to include mirrored surfaces at strategic areas during certain scenes so you can still see what's happening but are still locked to first person.
Pregnancy - Obviously this one is hard, and it's completely personal preference. It would be an interesting detriment to continued sexual exposure though. Increased rent prices. Potentially allow the girl to buy condoms or allow a minigame of sorts to avoid getting creampied during scenes.
More Diverse Monster Behavior - Include additional vectors of mitigating monster behavior such as a level of agitation. Take the first area where shining your torch is a death sentence immediately. Instead, let them slowly increase in agitation as you do things they don't like which increases their speed, their proclivity to attack, and their willingness to continue a chase. This could persist between trips to the general area and could progress to a point where she is actively hunted even without lighting a torch and could increase the severity of sexual abuse she is subjected to during scenes.
Lowering it could include sexual favors that she doesn't want to perform or simply avoiding the area for long enough. Additionally, grabbing the most expensive items from each area could also increase agitation especially if there is a nest for the creatures where you could take things they personally collected.
Knowing how much agitation is in a particular area could be yet another goblin service she has to pay for, like a goblin surveyor.
Grabbed - Potentially allowing a creature to grab and drag the female protagonist and require some kind of struggling mechanic might be interesting, though understandably that might be on the difficult side.
Stamina System - Some kind of stamina system, with penalties to max stamina based on her morale or corruption might also be interesting. Could also introduce other activities in the main hub she has to pay for to increase these statistics, such as taking baths or purchasing tasty foods. As it stands now, the girl is an olympic athlete capable of sprint at mach 2 outrunning everything is the caves with no detriment.
Torches and Darkness - The game is too bright. I know people complained, but I think that's because the torches themselves weren't luminous enough. As it stands now, there is little incentive to use them as I mentioned above. Upgrades could reduce agitation instead or make enemies not want to approach a few times. Torch should cast tons of light, but the environment should be basically pitch black outside of a few scant light sources.
More Forceful Animations - I love the fact that the girl has slight jiggles when she moves, but the sex animations are often so gentle she doesn't jiggle at all. More sharp thrusts and more rough treatment of the girl seem more fitting due to the subject matter of the game. Save the gentler stuff for when she approaches them for things she wants.
Also, I love the little bulge she gets when the goblins go to town on her, hopefully that gets expanded upon with bigger entities.
More Monsters - Duh, but I thought I'd add it anyway. The more monsters, the more animations, the more nests, and the more unique interactions the better. Even include contradictory monsters, such as in the first area where some monsters are attracted to the light, but others in the same area could be repelled by it. Introducing a balancing mechanic the player has to engage with.
Body Markings - Ability to turn these on or off. I'm not sure what the symbol over her womb is, but it looks out of place to me.
Speech Bubbles - No need to go all out on a voice budget, but just a simple pool of dialogue for her to draw from so we have a better idea how she is reacting to what's going on. If the perpetrating entity has nothing to say in response, just include elipses (...) to show that they heard her protestations but are just apathetic.
Simple lines like : "Please stop...", "I don't want to do this...", "Are you almost done? Please...", "Please let me go...", "Will you let me go after you're done?", "I'm scared, please stop.", "I'm sorry, I didn't mean to take things from your cave. I'll leave if you just let me go..."
All of that can go a LONG way.
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That's all I've got. As I said, I love the idea of the game and I'm not sure how much you have already planned out, but I thought I'd shoot some ideas out in case they might help. Feel free to ignore or use whatever.
I sincerely wish you luck dev and hope you can turn this into the game you want.