3/5 game, but a 1/5 porn game.
The game's not a bad take on the vampire survivor's genre, but I don't find it enjoyable for an extended period of time. Instead of the usual weapon stacking, you add NPCs into your blob of a party.
And I do mean "instead of".
There is no game design mechanic that utilizes the NPCs. Enemies still path to you like a standard vampires survivor game, and the game does not have any advanced unit control beyond "death ball around me".
Left alone, NPCs will follow you unless there's an enemy in range. If they see an enemy, NPCs will either stand in place and shoot, or jump into melee and stab their target, and only resume following you if they or the enemy dies.
Not that dying means anything. When an NPC loses all their health, they just return to your side and regenerate back to full HP.
That's the gist of the main gameplay loop. Vampire survivors, but instead of weapons you have a basic party system. Sure, the NPCs get in the way when you try to kite, but it's still a competently done system. 3/5
As for the porn part of the game...
I assume it's accessed through the "breakroom" part of the main menu, since that seems to spit out a random character interaction cutscene after every mission.
The only problem is the scenes are completely random and without context. There's no introduction to any of the characters, setting, or relationships, so it ends up being a random pile of lolrandom humour.
With that said, "lolrandom humour" is about how I'd describe the tone of the writing. It's grammatically adequate, but character interactions and dialogue are closer to tumblr shitposts rather than actual words spoken by believable characters.
Random access to maybe-not-porn scenes without context, poor writing, and a complete lack of cohesion is why I rate this as a 1/5 porn game. Only reason it's not 0 is because there's a clear art style the game aims for.
Note that it might still be a 0/5 porn game. I can't actually confirm the porn is accessed through the breakroom menu, because I can't be bothered to continue playing this game.
In conclusion, if you've already consumed all the other vampire survivors style games on the market, Solace Inc isn't a bad derivative of the genre. On the other hand, if you're just looking for a porn game, you can definitely do better than Solace Inc.