- Author's Saving Throw: The Updated Re-release adds an ending which shows Rorona as an adult after many complaints from fans from the two sides of the ocean. In the end, they ''did'' want to see a Rorona in her 30s.
- Fanon Discontinuity: Meruru was originally the last game in the Arland series, so players expected to be able to play as all three of the Arland alchemists to send off the series before the beginning of the next one. However, the developers apparently balked at the idea of having to depict Rorona (who starts the series at 14) in her 30s... thus writing a plotline where Rorona is mistakenly turned into an eight-year-old with no memories of her own history. She stays like this for the entire game. In the original PS3 version, she was never allowed to grow up either, implying that at best she was turned back into an amnesia ridden 14-year-old because Astrid finds that cuter. Fans pretty much bounced off of that idea since even a Butt-Monkey like Rorona deserved better than that, wanting to ignore it or write out that fate for her. Hence the need for the Author's Saving Throw from Plus to at least show one ending where Rorona became an adult again. This died off after Atelier Lulua was released and takes place later with Rorona finally allowed to be in her thirties with a daughter, hence her "child phase" went from being a disappointing send-off to just one of the many wacky things that happened to her.
- Game-Breaker: Synthesize the best equipment in your first playthrough and New Game+ is a cakewalk.
- The "Infinite Gio" build takes the Makina Domain and META bosses from face-meltingly hard to pathetically easy. You essentially build a Gio that can always go first, repeatedly using his Slash attack to generate consecutive hits, and then heal his own LP so he never runs out of attacks. It's the only set you can't build before New Game Plus due to both Gio and Makina Domain being unplayable in the first playthrough.
- Pamela's unique passive makes her absolutely critical in many strategies for tackling the Machina Domain end-game dungeon.
- Hilarious in Hindsight: Sterk's comments about a tiny rock that could endanger Meruru was funny on its own. Cue Meruru asking what kind of rock is dangerous anyway. Oh if she only knew... Lampshaded to hell and back in this video.
- Les Yay: As usual. If you think Totori and Mimi going Les Yay on each other is enough in the previous game, try putting Meruru between them.
- Surprisingly Improved Sequel: Generally the reaction the game got on both sides of the Pacific. In Japan it was the highest-reviewed Atelier game since the original release of Atelier Marie all the way back in 1997 (until Escha & Logy took that crown, anyway), and it's the best-selling Atelier game in ten dog's ages. The reaction was a little more varied among critics on the other side of the pond, but the high scores remain among the highest the entire franchise has ever seen in Anglophone publications by a county mile.
- The Scrappy: Rorona. She got turned into an eight year old between games, acts her new age, and her memories have become a complete mess. Though her Alchemic skills are still intact, she mainly refuses to use it willingly. A very large portion of fanbase was not happy with this turn. This is apparently because Gust couldn't stand to see her in her 30s. "Who wants to see a Rorona in her 30s? Not me, that's for sure!" This led to the Author's Saving Throw at the top of the page when it came time to make the Plus version.
- Astrid herself receives almost as much heat for doing the deed, and for not backing off from it in the original two endings resolving the plot thread. In both endings, Astrid uses Meruru's research on Youth Potions to create her own... but it only ages Rorona back to a 14-year-old with no memories of the time that passed, then quips the same line as above for her reasoning. In the "Witch's Tea Party" version of this, Astrid does the same thing but also forces Totori and Meruru to take it, rendering all 3 Arland protagonists and herself to be 14 forever, citing it as an "ideal age". While the latter ending was clearly meant to be fanservice by showing the three Arland protagonists at roughly the same age they started their own games at and in their original costumes, the fact that this still doesn't allow Rorona to grow up again did not sit well. Some fans even treat the endings as the Moral Event Horizon.
YMMV / Atelier Meruru: The Apprentice of Arland