I guess that depends on how quickly you made the game and how many games you could make like that. Would the paperwork be the same amount for your second game? If not, it sounds like it'd be worthwhile to try to churn out simple games this way in the evenings/weekends (think: flappy bird, 2048, etc) and make a decent profit on the side.
Did it take you less than about 8 full time months to make the game? If so you just made the median salary in the US for full time work.
I think the real question is whether he made more money than he would have otherwise in the same time, not where his earnings compare to the median employer.
Median salary in general is a meaningless comparison. You'd need to compare it to someone in their field.