One of the replies in that GameFAQs thread pretty much worked for me. After saving, I'd quit to the main menu and reload my save. Then, I'd wait ~10 seconds or so at the "Go to Towers" prompt, and then again when hovering over "Dawn Tower", and again at the "Yes/No" display. This seemed to work. The
light/dark mechanic has obviously been done to death, but it was a cool way to make those final few towers unique. The glitch but a bit of a damper on things, but I persevered.
Anyways, I just finished it (76%) and got the best ending. Happy with how it wrapped up. The last boss took a while, but was fairly easy once I took a few cracks at it.
Really neat game across the board. It's got a cool story that feels very modern, which clashes a bit with the game's setting, and it feels pretty fresh as a result. The towers are mostly well-put together and got more challenging and complex as the game progressed, doing a pretty good job of mixing Zelda-style dungeon progression with Souls-style urgency. And it makes great use of the Wii-mote throughout the game, most creatively with the boss fights. The camera got in the way a few times, but overall I thought it played well.
So yeah, I liked it a lot!