My review is a bit long, so I'll get to the point quickly: Playing the game is the worst part of the game.
The graphics are indeed nice, but they get old. I don't really care about the backgrounds, and the ornately detailed huge boss sprites become the opposite of nice to look at them after they kill you for the 20th time. The story is decent enough, but everyone says that it's cliche, and the promise of a story that I can already predict is not enough to keep me slogging through the travesty that is how the game plays.
Firstly, "power". The game's mechanic that is supposed to break up monotonous button mashing (spamming square is the ONLY way to get multi hit combos for some reason) is probably one of the worst ideas ever to be put into a game. Each attack takes power when you use it, and when you run out of power, you are stunned for quite a long while while it recovers. During this time you can't move, jump, attack, or guard, leaving you wide open to whatever enemy wants to take a swing at you. The major problem with this idea is that you really don't have that much power, and I constantly found that I would run out of power right before I finished an enemy, or even after, needing that last attack to take it down, only to find that the rest of the enemies swarming the level were waiting to finish ME off while I was stunned. I know reality doesn't play a large part, but I can't imagine what world exists in which a trained fighter would decide to stop and rest in the midst of a you-vs-20-other-guys fight just because he got a tired.
Guarding is another huge problem, fulled mainly by the strange decision to have both attack and guard accessed through the same button. I found guard to be the single most useless ability, mostly because whenever I needed to block something, I was in the midst of the obscenely long combos, or simply because even if you do block, you still take damage, and the attacks that do the most damage are generally unblockable. The damage you take is high enough to make the game relatively hard, but there are also many things wrong with it. I found the biggest problem to be that more often than not when you take over 100 damage, the game will show the hundreds first by itself, quickly replaced with the tens and ones, causing you to think that you took 34 damage instead of 234 damage, and when you only have 400 Hp, you tend to die unexpectedly many times before you figure out what the problem. The tougher "boss" enemies also will often turn around (assuming you are attacking them from behind) and begin attacking you during your combos (which you more often than not, can't stop once you've started), and many of the lesser enemies that you encounter also have the tendency to not flinch or stun when you expect them to, causing you to take alot of damage that is annoyingly unavoidable.
My above points can be easily dismissed by taking extra care and being cautious during battles to minimize damage, however this idea too is thrown off by the ranking system that determines the rewards you get at the end of the level. The time you took to complete the level and the amount of damage taken while doing it have equal weight, which become increasingly hard to juggle because A) without a map, you don't know how hard the particular area you are in is, so you cannot know except through trial and error how many enemies you will have to go through and if you need to expend items to beat them quicker, and B) many enemies have obscenely large amounts of life that you must hack through while avoiding their attacks.
The inventory system is a nightmare. You never have enough space for the continuous piles of crap you pick up, be it seeds, plants, or raw materials for crafting. Instead of having everything as a list, it's done in a ring fashion that displays a limited number of items depending on what bag they are in, forcing you to continuously shuffle through bags to find what you want. I found myself accidentally using or wasting items more than 30% of the time.
The crafting and buying system also contains problems, mostly in that everything you buy or make is thrown on the ground, even though 100% of the time, you're just going to pick it up, because you can't do anything other than hit it around when it's on the ground. More than anything, it is merely an annoying and blatantly needless step in managing your items.
The currency system seems to have little point other than forcing you to sort out the change you are paying in. Some of the coins have special value that others don't, which is one rationalization you might make, but it doesn't stand up very well to the point that other games have already gotten around this problem by making them inventory items as apposed to throwing them in with the rest of your currency.
Plants are yet another mechanic gone wrong. Even knowing the difficulty of a level, it is impossible without going through it to know how many "phozons" (experience points, no matter how you look at it) will appear. This led to a great many of my plants yielding nothing more than disappointment because the defeated enemies weren't numerous to grow the plant to maturity. It's also an interesting point that in the case of the plant that grows sheep, the sheep take more damage than some enemies to kill (you must kill them in order to get the items they drop).
Finally, the issue most mentioned in reviews: slowdown and loading. The slowdown is there, and it is bad, but it won't break the game as long as you can look past it. What really kills you is the loading, especially if you spend lots of time in the kitchen/cafe (a place to boost your HP) and backtracking through levels. I found that I spent almost double the time loading as I did getting things done when not progressing through the story than when I was, which seriously discouraged me from collecting items and leveling my character beyond what I got from sprinting through the required levels.
All in all, the game really does look nice. But the many counterintuitive decisions made with the gameplay ruin it entirely.