[tcfunk]

600 work hours give or take the 20,000 that got him the expertise required to sit down and write it in the first place. Do you end up with your own game engine, or a clone of Casey's game engine? That depends on what you already knew going into the series.

Not dismissing the value of the series here, just saying the average would-be game developer likely does not have the same skillset as Casey and, unless creating game engines is the goal, would be better served by Unreal or Unity.