This is easily one of my favourite games of my childhood, and is probably one, if not, my most played PS2 game. I still remember how scratched the disc was after playing it so much hahaha. It's not particularly an amazing game, but it's such a fun and nostalgic game for me and many others. It just oozes charm, and has a lot of interesting ideas in it.
It's essentially a very Legend of Zelda - esque kind of game, but not quite as good. However, it's definitely worth playing. The characters were very memorable, the soundtrack, the story, interesting puzzles, and surprisingly half decent voice-acting. Keep in mind though - this game's controls/combat is very, very clunky. Once you get used to it, it's manageable, but it's incredibly clunky and doesn't have too much depth to it.
The main challenge for this game would be the bugs and maybe porting. This game has a ton of bugs, some rendering you unable to complete certain side quests and content, audio, glitches, etc. The worst bug, in my opinion, is the audio bug where if you play the game for over a certain amount of time in a single sitting, the sound effects and music just stops, for whatever reason. It forces you to restart the game each time to get the sound back, and just kills the immersion.
I really hope GOG considers preserving this game, as it is a very fun game, and I could see a lot of people wanting to play this or giving it a try.