I'm at the exact same place as DCGX - 457 puzzles and 12 leftover gems. It doesn't feel like the proper ending, as there is so much in the game left unexplained:
- there's a frog with a sword on a path that can't seem to be reached (the character features on the cover)
- there's a door with '100' written on it that can't be opened
- there's another door in the teleport cave that can't be opened
- there's an area in the temple where an acolyte won't let you pass to the back halls
- you can't read the writing on mysterious panels or the sarcophagi
- one character goes to great lengths to describe a frozen village in the mountains that can't be reached.
Are these all macguffins, or is there more to the game still? I can't figure out what's left to do though, I can't find any more puzzles to do. I thought maybe I could trade the rock with a bow on it for something else with one of the characters, but I've talked to them all again and no-one is interested.