* Percentage: 80% is a strong score. Most students would be pleased with this result.
* Compared to others: You'd need to know the average score and standard deviation for the test administration to understand how you rank compared to your peers. An 80% might be above average, average, or even below average depending on the group taking the test.
* Specific goals: Your personal goals are important. If you aimed for a perfect score, you might feel differently than if you hoped to simply score above 75%.
In short, it's a solid score, indicating a good understanding of the tested material. However, its overall "goodness" needs more information for precise evaluation.