There isn't a way to replay the tutorial at the moment, but I can look into adding an option. In terms of a lose condition, the game ends after 10 turns (although you can extend this with many cards). If you're asking whether there's a specific "lose" situation, there isn't particularly- the goal is just to get as high of a score as you can, both to unlock new decks and compete with others, once the full version comes out.