Please, please give me advice on this, I know I fail at marketing and would love the help.
Mystery House, an adventure-horror experience with eerie, lo-fi visuals where you must escape from a mansion home to an alien-worshiping cult.
I would focus more on the alien-worshiping cult part. "Eerie, lo-fi visuals" is just telling people that the game is scary. So is "adventure-horror experience," although that's excusable because it describes the genre of the game. It's better to show people a detail of the game that will get them intrigued and wondering what the game is like than to just tell them what the game is like.
I didn't think the two phrases communicated the same thing, but now that you mention it I can see how it does.
What do you mean by "...a detail of the game..."? are you just referring to an aspect of the game, or something in the tone, etc?
I guess just an interesting fact about the game? Something about its story, or its mechanics, or anything really, as long as it's not obvious. So if I say my game is a puzzle platformer, that's pretty boring, but if I say it's about the struggles of a ghost trying to be an adult, that's a lot more interesting.
The pitch got me curious, but I have a hard time understanding the part "escape from a mansion home to an alien-worshiping cult". Shouldn't it be something like "escape from a mansion of an alien-worshiping cult" instead?