The game is fairly polished and quite stable, but Larian is still implementing features, so it isn't bug free, and a day one patch is planned.
Co-op is drop-in / drop-out. You can continue a co-op save in singleplayer, if you wish (or vise versa), or play co-op with a different person.
Dual dialogues allow both main characters (in singleplayer or co-op) to contribute to a decision or comment on a situation.
Release is on the 30th (delayed to add voices - see the latest
kickstarter update).
