For me, it’s a combination of factors as well. In no particular order:
(1) The genre is what pulls me in. There are some that I’m already quite fond of, so those games that fall in these categories (e.g. dark and gritty ones and superheroes) are ones I’d be more likely to purchase!
(2) The demo. There are those I fall in love with after the demo, and I’ll purchase it right after the free chapters end. If I am still unsure by the time I reach the end of the free chapters, I’ll look at reviews - on the PlayStore before I came on the forums, and now that I’m here, I’d look at the opinions people share here.
(3) As of now, there are a few series I’m actively following. Their sequels are the ones I’ll immediately hit purchase to once the book is released!