Bonus Material
Written by MSG Commander
Symphony of the Origin has a ton of bonus material, but if you don't know where to look for it you'll never find it all.
(The in-game menus do provide some hints, though, if you'd prefer to search it all out on your own.)
The first place to start would be with the SOP Shop. Though you do have to spend points for these purchases, you can earn SOP in-game (and, if you're playing the Amazon Underground version, you can buy all the SOP Points you want, for free.)
After you've explored all the options there, the next step is Group and Individual Training, followed by Crystal Locations, and finally, the Path to the Underwold.
Doing all the bonus material in this game will easily add several hours to your game time.