Another great game, kelarly, I had a lot of fun. There are some issues, though, that could drag some players down if they were unfortunate enough to encounter them. If you are still open to suggestions, here's a list, based on my playthrough notes. Spoiler alert for those who haven't completed the game yet!
(Possible) Bugs, mistakes etc.:
Game crashes (one-time only):
The game crashed when the trip on Kaze's boat began (during my first try), giving the following error message: "Script 'Caterpillar System' line 185: SystemStackError occurred. Stack level too deep."
After Praxis Raiko had beaten Nuraku (battle in Nivlanta Castle), the game crashed, giving the following error message: "Script 'Game_Map' line 292: SystemStackError occurred. Stack level too deep." Yes, very upsetting after three boss battles in a row and a lot of story scenes.
When Raiko awakened after the scenes in Inferno (start of chapter 2), the game crashed, giving the following error message: "Script 'Game_Character' line 226: SystemStackError occurred. Stack level too deep."
The game crashed when the party tried to jump over the first crevice in Roquewell Cavern (I accidentally closed the error message - no error code this time).
The game crashed after the battle against Virgil when the scene changed to Raditz in prison, giving the following error message: "Script 'Game_Character' line 135: SystemStackError occurred. Stack level too deep." The same crash with the same error message happened once before jumping from platform to platform in the Temple of Praxis.
The Dark Sorceress (boss in The Noxwood) could use "dispelga", even though she had been silenced before. Is this intentional? I never had the opportunity to check if Lucian could do the same.
Treasure chests that (supposedly) can't be reached:
First treasure chest on the Riverside map (lower left corner)
Treasure chest on the Eastern Grasslands map (lower left corner)
Treasure chest in Gialgatras Prison (adjacent to "first digit papers")
The Player can return to the Temple of Angels to get an EXP Ring (expendable, though, thanks to the Wicked Rose Ring), but there doesn't seem to be a way to leave the cave (i.e. the gate key room).
Other treasure chest problems:
One treasure chest on Grimoire Island (first map, upper right corner, containing a "dispel herb") doesn't appear on the minimap.
In Amon Sands (map after the boss battle) there's a treasure chest that's already open.
Items that can't be picked up:
The "Gold Coin" in Sami Swamp
The "Block of Gold" (if it's really one) in the Airship Hangar (Polestan, Raditz' House, lower right corner)
The "Pile of Gold" in Amon Sands (map when entering from Nivlanta, lower left corner)
The "Gold Coin" at Ecklesha Castle (outside, left side)
The "Gold Coin" in Kelteau Town
Miscellaneous:
When returning to the top of West Guard Tower, the party members encounter "silent replicas" of themselves. This is irritating, the more so as the player can find a "Block of Gold" here, which means that a later return has been taken into account.
During the Praxis Azura scene (before the battle with Lucian and after): There's a second Praxis Azura sprite instead of the Raiko sprite.
Weird bug in the Castle Halls: By approaching the save crystal, sometimes the party automatically goes up, thus entering the next screen in which a boss battle is automatically triggered. This can happen with or without the opportunity to use this save crystal, and it can even happen after loading the corresponding save file.
When entering Polestan from the south (after having backtracked from Sami Village at the beginning of chapter 2), the "we have to talk to Raditz" event is still active, preventing the party from leaving the city via the south exit. As the player can't backtrack to Sami Village the other way round (the way from the Secret Tunnel to the Temple of Praxis is still "blocked"), he's permanently trapped and can't complete the game. The trigger is still active in chapters 3 and 4, but doesn't pose a problem anymore thanks to the airship.
The "brittle wall tiles" in the "Hidden Tower" and in the "Siros Tower" shouldn't be passable.
The sign on the map where the entrance to Vedanta is blocked should say "To Vedanta – West" instead of "To Vedanta – East"
After the guy in front of Armistace Manor has moved away, he isn't "solid" anymore (the player can step on the tile he occupies). It's remarkable that this guy alone can cause a game over.
Twilight Temple: The player can't see if a switch has already been flipped.
Is there anyone who can use the "Morning Star"?
Incomplete dialogue in Ozvadelle Town house (lower right corner)
The Angel's Necklace doesn't protect against "zombify" (just like in "Passage of the Hollow Moon"), but here it doesn't even protect against "(black) death"?
During the endgame, two soldiers in Ecklesha Castle need updated dialogue (they still tell me that I have to hurry and that the king might be in danger).
The way from the Secret Tunnel to the Temple of Praxis is still "blocked" during the endgame.
When returning to the Temple of Praxis during the endgame, Azura, Willis and Kaze can still be seen standing/lying around.
Why is the ship still there when returning to Nivlanta Lighthouse during the endgame?
Why is the entrance to Ozvadelle Town on the World Map that far south, even though the town lies in the mountains to the north?
The Hidden Tower in Amon Sands can only be entered via the World Map when the player enters it via Amon Sands after getting the airship. For players who found the Hidden Tower without (possession of) the airship, the World Map entrance should be available immediately.
Improvement suggestions:
The game shouldn't be tagged as "Action Adventure RPG". Most players associate real-time battles with "Action Adventure", and you don't want players that only play RPGs with turn-based battles to shy away.
What's the point of giving the player the opportunity to pay for a fee-based rest at an inn when the player can use save crystals to heal for free?
This "failed/interrupted actions system" during battles (only to the player's disadvantage) is simply frustrating and aggravating, and contrary to what Luiishu535 wrote, this bug can't be avoided by not using the "steal" skill. Even without using the "steal" skill, party members' actions "overlap" so that only one action gets through, and enemies are able to "counter", rendering the own party member's action effectless. Especially the party's second turn is almost always completely wasted this way.
Skill descriptions etc. should distinguish between weaker and stronger versions of single-target skills as well as between single-target skills and multi-target skills.
The people in the Polestan Pub say the same things like the people in the Nivlanta Pub do. NPC dialogues are too often identical/alike in general. This is noticeable in particular when comparing NPC dialogues in Nivlanta to those in Ecklesha.
It's never fun when the player travels solo and the enemies are able to inflict status ailments like "sleep" or even "instant death" (Inferno - first time).
Inferno (first time): The player probably doesn't notice beforehand, but by entering the final map (in expectance of another save crystal), the way back to the save crystal at the beginning is permanently blocked.
It should be avoided to place two NPCs that look exactly the same in one building like in Vedanta Pub.
Nitpicking requires love. :) I'm looking forward to playing "Feral Dreams 2".