sorta like "mindblowing",
like a gun to the head is physical horror
where as psychedelic horror, is the use of "effects" to make it horrific,, sounds, aestetics, "immersion"
i suppose straight up jumpscares could be sorta the gaming version of a "gun to the head = physical horror" because its a cheap trick,
other horror games rely on much more, to make it more "psychedelic"... in the end its just a marketing term, since most of the games that use it arent truly psychedelic