Hey, everyone! I'm the developer of the game! Happy to see the game here, love the site, I think it's got a really enviable archival tradition.
Just to give a brief summary of the content that's currently in the game: right now it's a mix of FF, MFF, and MF - currently weighted more towards girl-girl but there's a little of everything.
As for what's planned, again, it's going to be a mix. In the update we're currently working on there's a female orc, a male fairy, and a harpy who kind of freestyles (I figured: harpies are monogendered, right, so they can probably hot-swap their junk). We kind of started with several of the more-humanoid monsters to make things a little more palatable for launch, but the monsters are, for the most part, going to get stranger as time goes on. We've got a take on an angel that I'm really excited for people to see. There's currently a total of 15 monsters planned in all - we'll be adding 3 per update.
On whether content is skippable: that's a no, I'm afraid. Since it's a sandbox structure you can go through each monster's story in whatever order you like, but the way the main story advances is predicated on "liberating" every monster in a given district. It's a LITTLE hard to get a feel for the flow since there's only one district currently, but here's how it's intended:
1. Prologue
2. Player does whatever they like until they've liberated every monster in a certain district
3. Main story advances
4. Player goes back to doing whatever they like until they've fully-liberated another district
5. Main story advances again
6. And so on until all of the monsters are liberated and we reach the end of the main story
To be clear, this isn't a branching paths/different endings situation. The game will be lightly-reactive in that the order in which you're clearing districts will affect certain things about the main story sections, and you might find that monsters from one district that you've liberated might make brief appearances in the stories of monsters from another district. Everyone will get the same ending, however.
Thanks to everyone for checking out the game! Hope you enjoy it!