While researching this hack I saw a few posts and comments complaining about bugs, like for example Whirlpool not working correctly or the game crashing in Victory Road. I believe there was a recent update as of August 2020. Their teams and levels are about the same from what I can remember of the original GBC game. All the gym leaders, E4, and trainers are the same. I would say it's a very faithful remake, there's no extra characters or cheesy dialogue to worry about. If that's what you're looking for I would definitely recommend giving it a spin, it's great for a nostalgia hit.
This is a mod of Liquid Crystal that's essentially vanilla Crystal on GBA with a few slight improvements. Just finished a playthrough of Crystal Advance and wanted to share some quick thoughts on the hack, hopefully this will be helpful for anyone considering it.