I have hereditary Red-Green color deficiency, so I expected to score about 2 or 3 on this test. I actually got 6, which quite surprised me.
Several of the earlier questions seem to depend on brightness differences rather than hue differences, and those are the ones that were easy for me.
The classical color perception test are the Ishihara tests (available in many libraries), which also used spot patterns, each with an imbedded letter or digit, one which is visible to someone with "normal" vision, and the other to someone like me with "defective" vision.