Let's get the negative out of the way first. Terrible poorly paced first half that contributed almost nothing to the narrative and had large empty areas with repetitive enemies, one of the least interesting plots in the series I've experienced, and combat that's overly exploitable by flash guard.

Once the second half began with the Primeval lands the game instantly improved as around 70% of the total bosses and actual meaningful interesting content comes around. The dungeons start presenting interesting mechanics and the towns don't overstay their welcome or bring progress to a halt. You also start getting some actually useful artifacts. If this game were solely this half I'd probably give the game a 4/5 instead.

Worth playing if you're a fan of the other Ys games or want an action rpg on the vita. On PC it's a drop of sand in the desert.