For most of my playthrough I had mixed feelings about Illusion of Gaia, and ultimately by the end I felt it was an underwhelming experience.

Gameplay, Dungeons:
Illusion of Gaia's strongest aspect is certainly its solid gameplay and well designed dungeons. The game primarily focuses on the dynamic between Will and one of his forms, Freedan the Dark Knight, when it comes to progressing dungeons and solving various puzzles. The strengths and skills of both characters are to be kept in mind to ensure thorough exploration and clearing of enemies, and I appreciate that one form doesn't necessarily make the other useless for that reason. The game also does not have a typical leveling system, instead encouraging the player to beat all enemies in an area to gain stat upgrades. I found it to be a good system that also ensured the player gets a good grip on combat and handling of the various enemies, and because of this system, exploration of dungeons also feels more natural. This way the player is both rewarded with stat upgrades and various treasures found through exploring.

Dungeons were probably my favourite part. I appreciate the variety in both aesthetic and enemies, keeping the experience fresh, and each dungeon has its own puzzle gimmick as well, none of which really frustrated me. The Sky Dungeon is definitely my favourite~

Boss fights tend to be on the difficult side, although the challenge certainly isn't consistent. That said, I found them fun, but there is a focus on pattern memorization that may lead to more trial and error than necessary with them. I also wish that there were more bosses, but ah well.

Shadow is the second form you obtained, and while he is fun to use, I do wish he could be obtained earlier. His lack of skills aside from the Aura (why it's used as an item, I have no idea) compared to Will and Freedan's rounded out repertoire also makes him feel more underwhelming than needed.

Story, Characters, and World:
The weaker aspects of the game relate to its story and characters mainly. It's just....kind of boring, honestly. There were a lot of interesting plot points the game explores, and there's a focus on the theme of light and dark as well the coming-of-age of Will and his friend group. It was handled in a way that didn't really keep me engaged; progression felt more abrupt than natural and some things just kinda happen, really.

I think a big part as to why I felt this way was that the characters themselves are for the most part, uninteresting too. Your group of friends show promising potential for character growth, but it never really gets explored or its just the bare minimum. It really just feels like they're there for plot progression only, sharing almost no interesting insights on what occurs around them nor do they seem to feel any sort of impact from them. Seth probably gets the worst of it. The most interesting I found were Lily, due in part how often she accompanies you in your journey, and Kara, the main heroine who actually does have decent character growth, and a developing relationship with Will. Overall, they're probably the most underwhelming aspect of this game.

What the game does better however is its world building and it's relation to the "dark" and "light" sides of human society. No two locations are the same, allowing us to see a variety of different aesthetics and cultures to each city. It helps that they tend to be interesting settings, such as the floating rafts of Watermia or the underground homes of the Angel Tribe. Most of these settings also show a "dark" side to them, which is to the evils or misfortunes of society. Slavery, Cannibalism, Suicide, stuff like that. It can come across jarring, going from more of a peaceful happy tone to this darker sad tone abruptly, but I feel that was the intention and as such, I appreciate the idea.

Other Notes:
The game is super linear and doesn't allow for much backtracking, however I believe there's an extra dungeon and bosses if you get all 50 red jewels. I didn't get them all, so I can't comment on it unfortunately.

Overall:
If I were to recommend Illusion of Gaia, it would be primarily for its gameplay really. The story and characters are unimpressive to say the least, so don't expect much in that regard.