It means Matthew Costello created several puzzle ideas years before The 7th Guest, and some of those early concepts—like the maze and bathroom spiders—were later used in The 11th Hour.
Interestingly, the exploration and strategic planning you use in stargazing is a lot like what you need in the B9 Game scanning the skies or game map, locking on to targets, and discovering new challenges. Whether you're navigating constellations or game levels, it's all about observation and timing.