The score of a game is always recorded as a percentage, where 100% means you have scored the maximum number of points available in that game. This can get a bit confusing for points-scoring games like bowling where the maximum in-game score is really 300 points, but where a score of 300 is recorded as 100% in the statistics! Likewise, in Poker the theoretical maximum score is 725 points (I think), but you are highly unlikely to ever record a score above 50% or so.
Completed games are also rated according to how many "moves" you had to make in order to reach the solution, and the time it took. The record holding game is the 100% game completed in the least amount of moves, and if all that is equal the game which was completed in the shortest time hold the record.
What is a move? That varies from game to game, but in most games anything you do that warrants SoliLuxe to add an Undo stage to its Undo list counts as a move.
For many games, the number of moves required to win is always the same. However, each time you use the Undo or Hint function also counts as a move in order to discourage cheating.
In click-and-match games like Memory and Cakewalk, each matching attempt counts as a move even if it is unsuccessful or if you abort it on purpose (by clicking on an illegal card or outside a card).
When you complete a game, a large graphic appears on top the layout declaring your achievement. In order to see the finished layout, click on the "completed" image to make it go away. (You'll probably tire of the "completed" fanfare accompanying the graphic pretty quickly, so it can be turned of on the Settings tab in the Options window.)
At the bottom of the layout you will also see a message informing you how many moves it took you to finish the game, and if you set a new record.
Click a game in the list in "Games" tab of the Options window to view your basic scoring statistics for that game.