We have so many things lying around that its pretty hard to hit FOMO for us. That said, we did buy Mina the Hollower immediately despite misgivings so I guess it's pretty arbitrary. Like I'm sure we'll like Deltarune a bunch but the effort of going back and replaying some chapters and so on keep us from scooping it up for now. Probably sick music and visual style that stand out are the best way sight unseen but word of mouth WILL do it from the right people.

So I guess the answer is "a friend saying yo check this out" and being way into it.