Beginning is hellish, because you have to get to Rei with full health, items, or both so you can fend off the six zombies in the plot battle. The enemies are way too fast on the map, though. You can fight, but they'll drain you too much and you'll lose the plot-fight; in truth, you must run till you get your powers. Once you have actual party members, it gets a little easier.
Everything's used....too little. You get a music box-to-rest-zone setup...that is only used once(Thus what you buy there is all you get, and you don't get revival items). You get puzzles involving your abilities....that only gets used for one sequence. 10 characters total, of which you'll use 3 and a fourth in 2 battles. And I'm not convinced the 'choice of characters' is an actual choice. I suspect they learn the same moveset, which makes sense-9 sisters, three choices, three per element.(The biggest risk is Tomo's area doesn't give you a Music Box, which would render things even harder.)
The game's short. Which is both good and bad.