Getting X.P.

Experience points are one of the great leveling agents in games. You can take any form of expertise,
quantify it,
and alter it's point rewards
vis-a-vis
other dimensions used in the game.

You can assign a certain number of points for activities that lead to "player advancement"
New Player Levels are often reached through a combination of activities that add up experience points to reach a certain threshold.

For teachers, this is akin to changing with the scales on assignment rubrics.
In a game, you can put an arbitrary rule and quantify things that otherwise wouldn't be permissible.
In learning assessment too, you can change the emPHASis on what knowledge you measure, how much of a domain you measure, and how thorough the connections between these ideas.

3D Game Mechanics, like Learning Assessment is complex. It's hard to get your arms around these concepts
because both of them require the capacities of perception, knowledge, and action within SYSTEMS.

Systems are notoriously difficult to think about and work on.

Operational systems for both Game Mechanics and Learning Assessment can easily be codified to make a game WORK - but that doesn't make such codification either FUN nor a good learning transfer. Like bad singing, a bad game is not hard to create - it's a decent one that's so hard to find.

Quest: Make a Bad Game: If you were to make a rubric that described a ridiculously horrible game, what would you put in it? Try it.