Good job!
The writing is pretty decent, the dialogues are good. It is obvious that Erik is a douchebag, so he couldn't seduce Ophelia on his own. And this is the only thing i didn't like. He had to use drugs in the dessert. I know drugs used to enchance arousal and sexual experiences are part of the main game. But i swear almost nobody can seduce a women without them in the world of Power Vacuum.
Oh and I honestly didn't know Erik was a character from other games. But from what i read in the comments, looks like he is an asshole everywhere.
The models are looking really good. Ophelia is beautiful as always. My favourite side character was Christine ... She is really pretty.
The foreplay segment of the sex scene was so hot. The titjob part was awesome and the animations were good too. In the vaginal sex part the animations are also nice. There is room for improvement, but they are already good. I liked that there were a bunch of positions and Ophelia with her hair down was a nice touch at the end.
But, this is just my honest opinion.
Overall i enjoyed this fan game. I will look forward your future project Sumatra!