A lot of people have said it's the kind of game you need to experience for yourself. I'm not sure i agree with that claim myself, but i can see why people feel that way. I started by watching Cryaotic play it. There were always at least a few comments telling people "play it for yourself first!!", though i think it was more the charm of the game itself that won me over.
It isn't a "walking simulator", like Dear Esther or Gone Home are sometimes called. Whether you talk or fight your way through, you will have combat encounters, and you have to dodge enemy attacks either way. I hear the combat system compared a lot to EarthBound, but since i've never played EarthBound i can't compare it. There isn't an "easy" mode as such, but i managed it and i'm far from a fighting game expert, and in some of the climactic final battles you'll reach a point where you can't lose.
If you're unsure about buying it, i think i'd recommend watching someone play at least some of it -- you'll get a few spoilers, sure, but you'll also get the basic idea of how the game works and the kind of "feel" it has, hopefully enough to work out if you'd like it.
There are a couple same-sex relationships that you have to encourage to get the best possible ending. It's annoying, but if you squint and tilt your head sideways, you can almost pretend they're just friends. It never gets more explicit than a peck on the cheek in the end credits.