Tip for going for max points - If your score doesn't match these values at the end of each floor you must start again.
Floor 1 - 11
Floor 2 - 24
Floor 3 - 39
Floor 4 - 56
Floor 5 - 75
Floor 6 - 96
Floor 7 - 119
And if you've done all correctly, the Throne Room should contain 20 more gems, bringing you up to 139. Hope this helps!