These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Atelier Iris 2: The Azoth of Destiny
Cliché Storm: The storyline is fairly standard JRPG fare; you could pretty much guess half the stuff that's going to happen next as you play it. Much like its predecessor, the game's strengths lie in its smooth combat system, the charm of the characters, and the franchise's iconic crafting system.
Contested Sequel: A lot of people seems to agree that the first game was superior with better plot, more sympathetic characters and much more well animated sprites and graphics in general.
Game Breaker: Fee's Endless Blades skill. You get it very early, and it pretty much fills up the bonus gauge with only one usage.
It's very easy, through some playing around with the synthesis system, to get all your healing items to heal twice as much and heal the entire party at the same time. Then, you can use the infinite elements all around Eden to make as much as you want. This can be done by Ch. 7.
That One Attack: Crimson Split. AND Crimson Moon. AND Shadow Azoth. Basically everything the Final Boss throws at you that aren't debuffs. In an otherwise fairly easy game, Gust does at least provided a worthy and legitimate challenge at the end.