Curious as to if anyone's played Shallie yet.
From everything I've read there's no time limit. At all. Not even a really lenient one like Totori/Meruru/Ayesha. It's just completely gone. Events instead progress based on a different system entirely. "Life gauge" or something, which changes based on how many actions (eg, Alchemy, moving around the map) you've taken.
Now, I can comment on the OST; it has songs partially in English! Well, as close to English as non-speaking Japanese singers tend to get, so it sounds a bit like the vocal songs in, say, XIII-2. I greatly prefer this vocal OST to Escha's, but find it inferior to Ayesha's. Narcolepsist gets special mention as being my second favorite song in the Dusk subseries (it's one you really have to listen to fully to appreciate).
Also, Ayesha appears! It's just an unimportant cameo, but she has a different color scheme now.