Ar Tonelico: Melody Of Elemia

General Tips

• Save in multiple slots. Unless playing the Japanese Best Of re-release version which fixes it, there is a rare but possible bug in the very late game on Misha's path that can stop the game from progressing. Having a previous save to go back to will likely get you around it should it trigger.

• The automap doesn't necessarily show every exit route, so make sure to explore yourself too.

• You can always escape from fights without penalty or chance for failure from your Reyvateil's combat menu. You can also eventually craft an item (which then becomes buyable from shops) that eliminates random encounters completely until you either exit the dungeon or load a save.

• Most Purple Grathnode Crystals with effects like "attacks cause x status effect" or "increased critical chance" do nothing when placed on Reyvateil equipment. You'll have to add such effects directly to the individual spells with red Grathnode Crystals once the option becomes available, although even then "spell causes x status effect" seems to do nothing much of the time.

• The main route/ending branch happens early into Phase 2, when you make the choice of which one of two groups to accompany. Make a separate save before this if you intend to replay for the other path. There's also a smaller branch choice late in Phase 1 which doesn't lock you into a path, but affects the events immediately after it.

• Higher item quality (C -> B -> A -> S) does not make gear provide bigger bonuses, it only affects what kind of Grathnode Crystal you can convert it into (once you unlock the system to do so). While you can get crystals with some very strong effects this way, the game isn't especially difficult even if you ignore item quality completely and never convert items into crystals.

• Shops often add new stock after you advance the plot, including new recipe cards. Many consumables and crafting ingredients you craft will also be added to various shops around the world, with the same item quality as the one you crafted. In other words, if you've crafted at least one S-quality version of an ingredient, you can then simply buy more S-rank versions of that same ingredient.

• There is a shop that sells packs of essentially trading cards in Firefly Alley, one of the main cities. These mainly unlock lore entries for enemies and characters but they aren't really worth bothering with, they get prohibitively expensive and are both random and include duplicates. You'll likely have to rely on cheats if you really want to read all the entires they unlock.

Reyvateils & Cosmosphere

• Always take the time to make sure your Reyvateil has a lot of Divepoints and go into their Cosmosphere to level up your relationship with them. Not only does this power them up, but by visiting various places in their mind you will gain new spells and costumes, which will give them bonuses.

• Much later on in the game your Cosmosphere progress will grind to a halt until you get certain items from story related missions. Otherwise there is no limit on how deep into each Reyvateil's Cosmosphere you can go. If you want to break the already-fragile game over your knee, you should finish all of the levels for each girl.

• You will get a special prize for reaching Level 5 in a Cosmosphere, usually given to you the first time you rest after completing the level. Misha's in particular is useful until pretty much the end of the game, and it's recommended you get it as soon as possible.

• Very nearly every item you craft has a unique conversation attached to it depending on which Reyvateil you have in your active party at the time. They might even give unique name suggestions for the items.

• You can't unlock every Reyvateil talk topic in one playthrough, as some are mutually- or path-exclusive. Many also have very specific timings and requirements that you'll likely miss without a guide, so it's better not to stress too much about it. Doing things like using every costume enough times, revisiting old locations or casting each new spell at least once will net you most of them.

Combat

• Elemental Grathnode Crystals and buff spells are amazingly powerful, since they grant additional damage based on your base attack damage. Throw 100 points into, say, Wind, and boom, double damage. If you don't mind being even more overpowered, throw as many of those crystals that drastically boost attack power in exchange for your defense. You'll be able to one-shot just about everything. Of course, you'll also be pretty much one-shotted by everything, so watch it.

• The combat system seems obtuse at first, but it's simple once you see the basic pieces. Note that this only applies once you actually have a Reyvateil in your party, essentially past the tutorial dungeons.

1. Your first main goal is to fill up the small red bar at the top of the combat UI to unlock higher Harmocrystal levels (the slots to the left), up to 3 crystal slots. You mainly do this by hitting enemies with magic, the more charged up the spell, the more the bar fills. 2000% charge with the basic attack spell tends to fill up the bar in one go, but piecemeal like 1000% + 1000% works too.
2. Your second main goal is to fill up those Harmocrystal slots you've unlocked by having the larger red and blue bars at the bottom meet. You mainly do this by hitting enemies with offensive skills like Lyner's 'Impulse'. Normal attacks progress the bar too, but skills do it much faster. For every crystal slot you fill, the stronger you get and the more loot you'll get. Fill up all three for the best results.
3. Unlike skills, normal attacks do temporarily cause enemies to take multiplied damage from your spells (indicated by an increasing number next to the enemy). This is mostly important in boss fights, but it does also reduce the amount of charge required to unlock Harmocrystal slots accordingly, so for example hitting an enemy once right before throwing a spell at them means you'll need half as much charge (2000% -> 1000%) to fill up the small red bar.
4. There's also a bunch of weird stats in your Reyvateil's equipment/status menu, but the only really important thing there is the moving Influence gauge at the bottom. The faster this moves, the faster the blue and red bars accumulate which makes it easier to reach high ranks in battle. GD Resist reduces MP costs which is okay but MP is rarely an issue, and the Burst Speed graph seems to only make minimal difference.