If you've played ToP, you'll notice some nice touches in ToS, since ToS is far in the past of the world of ToP. Things like...

[spoilers]When Lloyd and Colette are talking about Treant's Forest, and how they hope everyone can see it in the future, it remains exactly the same as it was in the future, still not allowing half-elves in, still needing the king's permission to enter Heimdall and the Ymir Forest.[/spoilers]

Or

[spoilers]Lloyd uses the Vorpal Sword and Flamberge to split the power of the Eternal Sword, in ToP, Cless and Klarth use Origin to reforge the Vorpal Sword and Flamberge back into the Eternal Sword for him to use and reveal Dhaos' castle which exists out of time and space, much like Cruxis.[/spoilers]