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.
Fridge Brilliance: When Marduk fought Gemma, he gathered the Army of the Seven Winds, which consisted of volunteers from each world shell. Throughout the main game, Doskias seems to only ever employ Chosen soldiers, while Maya ultimately ends up recruiting characters from each world shell, giving a subtle hint that she is the true savior of Septerra.
Several bosses in this game are hard, but the Sonic Lava Boss is particularly nasty. It consists of three legs and an untargetable head. The legs have extremely high defenses, you have to destroy all three, and the head will revive them if you don't kill the other two fast enough. The three legs also use powerful fire attacks, and the head has a nasty hit-all attack as well. Oh, and you have to spend your accessory slot on Earplugs to even fight it at all.
The Mining Helgak, fought shortly after the Sonic Lava Boss, is also fairly hard. It has a flap of skin around its head which you have to hit five times to get it to retract. Then you attack it once and the covering returns, meaning you essentially damage it with one out of six attacks. Oh, and if you don't attack it quickly enough while it's vulnerable, it uses a super attack on you and the foreskin moves back to it's protective position. It also has two antannae that shoots beams at you that seem to act independantly. Oh yeah, and did I mention that it looks like a penis? The scene strongly reminds of Hopeless Boss Fight in the Ocean Palace in Chrono Trigger, but at least this boss isn't undefeatable, just has a lot of hit points.