I had no clue AoC is a one-man-band project. With that in mind, how diversified are these puzzles? Wouldn't it be repetitive for people doing it year over year

I had no clue AoC is a one-man-band project. With that in mind, how diversified are these puzzles? Wouldn't it be repetitive for people doing it year over year or is Eric one excessively creative individual?