Even better, rearrange your database to store immutable facts instead of mutable state.

In this example, you might have a goal_completion table to which you append a row when the player completes a goal, instead of changing an existing row. The table could have suitable unique constraints to make sure that each player can only complete a goal once.

This way, it is much harder for your data to accidentally be modified in a way that it becomes wrong.

This also gives you a way to store facts about the completion for free, such as a timestamp for each goal completion. And having data like timestamps is really useful for auditing, debugging and testing.