A sort of "slice of life" simulator, where you play a nosy ghost with the ability to bend people to your will. Sort of.
Actually, it's like The Walking Dead, except your choices have actual impact. No, but really. It's also like Dear Esther or Gone Home, but with a little bit more actual gameplay (I highly recommend the "Stealth" difficulty level), and your decisions throughout impact the entire story and the Kaplans' relationships as well as the ending. You have to balance the father's career as a writer (side note: as a writer myself, Dan hit a little too close to home), the mother's stalled career as a painter, and their son's emotional turmoil--or you can fail miserably. Doom everyone to a life of misery, focus on one family member at the expense of the others, or flail around looking for a happy medium; the choice is yours.
I'd definitely recommend picking this up on sale--$15USD is unfortunately steep for such a short game--and then setting aside an uninterrupted 2-3 hours with a cup of tea or something to play it all the way through. It's well worth your time.